<!DOCTYPE html>
<html lang="cn-ZH">
  <head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width,initial-scale=1">
    <title>Rust入门（七）：编写测试 | 摸鱼老萌新</title>
    <meta name="description" content="Front end project and tips sharing">
    <link rel="stylesheet" href="/assets/style.8f1fef60.css">
    <link rel="modulepreload" href="/assets/app.75d9ecf2.js">
    <link rel="modulepreload" href="/assets/articles_rust_07.编写测试.md.bd7d6015.lean.js">
    
    <script id="check-dark-light">(()=>{const e=localStorage.getItem("vitepress-theme-appearance"),a=window.matchMedia("(prefers-color-scheme: dark)").matches;(!e||e==="auto"?a:e==="dark")&&document.documentElement.classList.add("dark")})();</script>
  </head>
  <body>
    <div id="app"><div class="Layout" data-v-c6a644e1><!--[--><!--]--><!--[--><span tabindex="-1" data-v-151f2593></span><a href="#VPContent" class="VPSkipLink visually-hidden" data-v-151f2593> Skip to content </a><!--]--><!----><header class="VPNav" data-v-c6a644e1 data-v-a71a30f1><div class="VPNavBar has-sidebar" data-v-a71a30f1 data-v-6f1d18b5><div class="container" data-v-6f1d18b5><div class="VPNavBarTitle has-sidebar" data-v-6f1d18b5 data-v-d5925166><a class="title" href="/" data-v-d5925166><!--[--><!--]--><!--[--><img class="VPImage logo" src="/logo.jpg" data-v-e13a1912><!--]--><!--[-->摸鱼老萌新<!--]--><!--[--><!--]--></a></div><div class="content" data-v-6f1d18b5><!--[--><!--]--><!----><nav aria-labelledby="main-nav-aria-label" class="VPNavBarMenu menu" data-v-6f1d18b5 data-v-f83db6ba><span id="main-nav-aria-label" class="visually-hidden" data-v-f83db6ba>Main Navigation</span><!--[--><!--[--><div class="VPFlyout VPNavBarMenuGroup" data-v-f83db6ba data-v-6ffb57d3><button type="button" class="button" aria-haspopup="true" aria-expanded="false" data-v-6ffb57d3><span class="text" data-v-6ffb57d3><!----> 前端 <svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" viewbox="0 0 24 24" class="text-icon" data-v-6ffb57d3><path d="M12,16c-0.3,0-0.5-0.1-0.7-0.3l-6-6c-0.4-0.4-0.4-1,0-1.4s1-0.4,1.4,0l5.3,5.3l5.3-5.3c0.4-0.4,1-0.4,1.4,0s0.4,1,0,1.4l-6,6C12.5,15.9,12.3,16,12,16z"></path></svg></span></button><div class="menu" data-v-6ffb57d3><div class="VPMenu" data-v-6ffb57d3 data-v-1c5d0cfc><div class="items" data-v-1c5d0cfc><!--[--><!--[--><div class="VPMenuLink" data-v-1c5d0cfc data-v-e8e0fb1d><a class="VPLink link" href="/articles/basic/index.html" data-v-e8e0fb1d data-v-3c355974><!--[-->基础<!--]--><!----></a></div><!--]--><!--[--><div class="VPMenuLink" data-v-1c5d0cfc data-v-e8e0fb1d><a class="VPLink link" href="/articles/vue/index.html" data-v-e8e0fb1d data-v-3c355974><!--[-->Vue<!--]--><!----></a></div><!--]--><!--[--><div class="VPMenuLink" data-v-1c5d0cfc data-v-e8e0fb1d><a class="VPLink link" href="/articles/react/index.html" data-v-e8e0fb1d data-v-3c355974><!--[-->React<!--]--><!----></a></div><!--]--><!--[--><div class="VPMenuLink" data-v-1c5d0cfc data-v-e8e0fb1d><a class="VPLink link" href="/articles/mini/index.html" data-v-e8e0fb1d data-v-3c355974><!--[-->小程序<!--]--><!----></a></div><!--]--><!--[--><div class="VPMenuLink" data-v-1c5d0cfc data-v-e8e0fb1d><a class="VPLink link" href="/articles/electron/index.html" data-v-e8e0fb1d data-v-3c355974><!--[-->Electron<!--]--><!----></a></div><!--]--><!--[--><div class="VPMenuLink" data-v-1c5d0cfc data-v-e8e0fb1d><a class="VPLink link" href="/articles/web3d/index.html" data-v-e8e0fb1d data-v-3c355974><!--[-->Web3D<!--]--><!----></a></div><!--]--><!--[--><div class="VPMenuLink" data-v-1c5d0cfc data-v-e8e0fb1d><a class="VPLink link" href="/articles/rust/01.%E5%9F%BA%E7%A1%80%E5%85%A5%E9%97%A8.html" data-v-e8e0fb1d data-v-3c355974><!--[-->Rust<!--]--><!----></a></div><!--]--><!--[--><div class="VPMenuLink" data-v-1c5d0cfc data-v-e8e0fb1d><a class="VPLink link" href="/articles/other/vitepress/01.vitepress%E7%9A%84%E6%90%AD%E5%BB%BA.html" data-v-e8e0fb1d data-v-3c355974><!--[-->其他<!--]--><!----></a></div><!--]--><!--]--></div><!--[--><!--]--></div></div></div><!--]--><!--[--><a class="VPLink link VPNavBarMenuLink" href="/leetcode/LEET_CODE%E9%A2%98%E8%A7%A3/47.%20%E5%85%A8%E6%8E%92%E5%88%97%20II.html" data-v-f83db6ba data-v-47a2263e data-v-3c355974><!--[-->算法<!--]--><!----></a><!--]--><!--[--><a class="VPLink link VPNavBarMenuLink" href="/intent/" data-v-f83db6ba data-v-47a2263e data-v-3c355974><!--[-->项目<!--]--><!----></a><!--]--><!--]--></nav><!----><div class="VPNavBarAppearance appearance" data-v-6f1d18b5 data-v-a3e7452b><button class="VPSwitch VPSwitchAppearance" type="button" role="switch" aria-label="toggle dark mode" aria-checked="false" data-v-a3e7452b data-v-1899cd41 data-v-086e8519><span class="check" data-v-086e8519><span class="icon" data-v-086e8519><!--[--><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" viewbox="0 0 24 24" class="sun" data-v-1899cd41><path d="M12,18c-3.3,0-6-2.7-6-6s2.7-6,6-6s6,2.7,6,6S15.3,18,12,18zM12,8c-2.2,0-4,1.8-4,4c0,2.2,1.8,4,4,4c2.2,0,4-1.8,4-4C16,9.8,14.2,8,12,8z"></path><path d="M12,4c-0.6,0-1-0.4-1-1V1c0-0.6,0.4-1,1-1s1,0.4,1,1v2C13,3.6,12.6,4,12,4z"></path><path d="M12,24c-0.6,0-1-0.4-1-1v-2c0-0.6,0.4-1,1-1s1,0.4,1,1v2C13,23.6,12.6,24,12,24z"></path><path d="M5.6,6.6c-0.3,0-0.5-0.1-0.7-0.3L3.5,4.9c-0.4-0.4-0.4-1,0-1.4s1-0.4,1.4,0l1.4,1.4c0.4,0.4,0.4,1,0,1.4C6.2,6.5,5.9,6.6,5.6,6.6z"></path><path d="M19.8,20.8c-0.3,0-0.5-0.1-0.7-0.3l-1.4-1.4c-0.4-0.4-0.4-1,0-1.4s1-0.4,1.4,0l1.4,1.4c0.4,0.4,0.4,1,0,1.4C20.3,20.7,20,20.8,19.8,20.8z"></path><path d="M3,13H1c-0.6,0-1-0.4-1-1s0.4-1,1-1h2c0.6,0,1,0.4,1,1S3.6,13,3,13z"></path><path d="M23,13h-2c-0.6,0-1-0.4-1-1s0.4-1,1-1h2c0.6,0,1,0.4,1,1S23.6,13,23,13z"></path><path d="M4.2,20.8c-0.3,0-0.5-0.1-0.7-0.3c-0.4-0.4-0.4-1,0-1.4l1.4-1.4c0.4-0.4,1-0.4,1.4,0s0.4,1,0,1.4l-1.4,1.4C4.7,20.7,4.5,20.8,4.2,20.8z"></path><path d="M18.4,6.6c-0.3,0-0.5-0.1-0.7-0.3c-0.4-0.4-0.4-1,0-1.4l1.4-1.4c0.4-0.4,1-0.4,1.4,0s0.4,1,0,1.4l-1.4,1.4C18.9,6.5,18.6,6.6,18.4,6.6z"></path></svg><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" viewbox="0 0 24 24" class="moon" data-v-1899cd41><path d="M12.1,22c-0.3,0-0.6,0-0.9,0c-5.5-0.5-9.5-5.4-9-10.9c0.4-4.8,4.2-8.6,9-9c0.4,0,0.8,0.2,1,0.5c0.2,0.3,0.2,0.8-0.1,1.1c-2,2.7-1.4,6.4,1.3,8.4c2.1,1.6,5,1.6,7.1,0c0.3-0.2,0.7-0.3,1.1-0.1c0.3,0.2,0.5,0.6,0.5,1c-0.2,2.7-1.5,5.1-3.6,6.8C16.6,21.2,14.4,22,12.1,22zM9.3,4.4c-2.9,1-5,3.6-5.2,6.8c-0.4,4.4,2.8,8.3,7.2,8.7c2.1,0.2,4.2-0.4,5.8-1.8c1.1-0.9,1.9-2.1,2.4-3.4c-2.5,0.9-5.3,0.5-7.5-1.1C9.2,11.4,8.1,7.7,9.3,4.4z"></path></svg><!--]--></span></span></button></div><div class="VPSocialLinks VPNavBarSocialLinks social-links" data-v-6f1d18b5 data-v-738bef5a data-v-f6988cfb><!--[--><a class="VPSocialLink" href="https://github.com/aiai0603" target="_blank" rel="noopener" data-v-f6988cfb data-v-e57698f6><svg role="img" viewBox="0 0 24 24" xmlns="http://www.w3.org/2000/svg"><title>GitHub</title><path d="M12 .297c-6.63 0-12 5.373-12 12 0 5.303 3.438 9.8 8.205 11.385.6.113.82-.258.82-.577 0-.285-.01-1.04-.015-2.04-3.338.724-4.042-1.61-4.042-1.61C4.422 18.07 3.633 17.7 3.633 17.7c-1.087-.744.084-.729.084-.729 1.205.084 1.838 1.236 1.838 1.236 1.07 1.835 2.809 1.305 3.495.998.108-.776.417-1.305.76-1.605-2.665-.3-5.466-1.332-5.466-5.93 0-1.31.465-2.38 1.235-3.22-.135-.303-.54-1.523.105-3.176 0 0 1.005-.322 3.3 1.23.96-.267 1.98-.399 3-.405 1.02.006 2.04.138 3 .405 2.28-1.552 3.285-1.23 3.285-1.23.645 1.653.24 2.873.12 3.176.765.84 1.23 1.91 1.23 3.22 0 4.61-2.805 5.625-5.475 5.92.42.36.81 1.096.81 2.22 0 1.606-.015 2.896-.015 3.286 0 .315.21.69.825.57C20.565 22.092 24 17.592 24 12.297c0-6.627-5.373-12-12-12"/></svg></a><!--]--></div><div class="VPFlyout VPNavBarExtra extra" data-v-6f1d18b5 data-v-e89b88d7 data-v-6ffb57d3><button type="button" class="button" aria-haspopup="true" aria-expanded="false" aria-label="extra navigation" data-v-6ffb57d3><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" viewbox="0 0 24 24" class="icon" data-v-6ffb57d3><circle cx="12" cy="12" r="2"></circle><circle cx="19" cy="12" r="2"></circle><circle cx="5" cy="12" r="2"></circle></svg></button><div class="menu" data-v-6ffb57d3><div class="VPMenu" data-v-6ffb57d3 data-v-1c5d0cfc><!----><!--[--><!--[--><!----><div class="group" data-v-e89b88d7><div class="item appearance" data-v-e89b88d7><p class="label" data-v-e89b88d7>Appearance</p><div class="appearance-action" data-v-e89b88d7><button class="VPSwitch VPSwitchAppearance" type="button" role="switch" aria-label="toggle dark mode" aria-checked="false" data-v-e89b88d7 data-v-1899cd41 data-v-086e8519><span class="check" data-v-086e8519><span class="icon" data-v-086e8519><!--[--><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" viewbox="0 0 24 24" class="sun" data-v-1899cd41><path d="M12,18c-3.3,0-6-2.7-6-6s2.7-6,6-6s6,2.7,6,6S15.3,18,12,18zM12,8c-2.2,0-4,1.8-4,4c0,2.2,1.8,4,4,4c2.2,0,4-1.8,4-4C16,9.8,14.2,8,12,8z"></path><path d="M12,4c-0.6,0-1-0.4-1-1V1c0-0.6,0.4-1,1-1s1,0.4,1,1v2C13,3.6,12.6,4,12,4z"></path><path d="M12,24c-0.6,0-1-0.4-1-1v-2c0-0.6,0.4-1,1-1s1,0.4,1,1v2C13,23.6,12.6,24,12,24z"></path><path d="M5.6,6.6c-0.3,0-0.5-0.1-0.7-0.3L3.5,4.9c-0.4-0.4-0.4-1,0-1.4s1-0.4,1.4,0l1.4,1.4c0.4,0.4,0.4,1,0,1.4C6.2,6.5,5.9,6.6,5.6,6.6z"></path><path d="M19.8,20.8c-0.3,0-0.5-0.1-0.7-0.3l-1.4-1.4c-0.4-0.4-0.4-1,0-1.4s1-0.4,1.4,0l1.4,1.4c0.4,0.4,0.4,1,0,1.4C20.3,20.7,20,20.8,19.8,20.8z"></path><path d="M3,13H1c-0.6,0-1-0.4-1-1s0.4-1,1-1h2c0.6,0,1,0.4,1,1S3.6,13,3,13z"></path><path d="M23,13h-2c-0.6,0-1-0.4-1-1s0.4-1,1-1h2c0.6,0,1,0.4,1,1S23.6,13,23,13z"></path><path d="M4.2,20.8c-0.3,0-0.5-0.1-0.7-0.3c-0.4-0.4-0.4-1,0-1.4l1.4-1.4c0.4-0.4,1-0.4,1.4,0s0.4,1,0,1.4l-1.4,1.4C4.7,20.7,4.5,20.8,4.2,20.8z"></path><path d="M18.4,6.6c-0.3,0-0.5-0.1-0.7-0.3c-0.4-0.4-0.4-1,0-1.4l1.4-1.4c0.4-0.4,1-0.4,1.4,0s0.4,1,0,1.4l-1.4,1.4C18.9,6.5,18.6,6.6,18.4,6.6z"></path></svg><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" viewbox="0 0 24 24" class="moon" data-v-1899cd41><path d="M12.1,22c-0.3,0-0.6,0-0.9,0c-5.5-0.5-9.5-5.4-9-10.9c0.4-4.8,4.2-8.6,9-9c0.4,0,0.8,0.2,1,0.5c0.2,0.3,0.2,0.8-0.1,1.1c-2,2.7-1.4,6.4,1.3,8.4c2.1,1.6,5,1.6,7.1,0c0.3-0.2,0.7-0.3,1.1-0.1c0.3,0.2,0.5,0.6,0.5,1c-0.2,2.7-1.5,5.1-3.6,6.8C16.6,21.2,14.4,22,12.1,22zM9.3,4.4c-2.9,1-5,3.6-5.2,6.8c-0.4,4.4,2.8,8.3,7.2,8.7c2.1,0.2,4.2-0.4,5.8-1.8c1.1-0.9,1.9-2.1,2.4-3.4c-2.5,0.9-5.3,0.5-7.5-1.1C9.2,11.4,8.1,7.7,9.3,4.4z"></path></svg><!--]--></span></span></button></div></div></div><div class="group" data-v-e89b88d7><div class="item social-links" data-v-e89b88d7><div class="VPSocialLinks social-links-list" data-v-e89b88d7 data-v-f6988cfb><!--[--><a class="VPSocialLink" href="https://github.com/aiai0603" target="_blank" rel="noopener" data-v-f6988cfb data-v-e57698f6><svg role="img" viewBox="0 0 24 24" xmlns="http://www.w3.org/2000/svg"><title>GitHub</title><path d="M12 .297c-6.63 0-12 5.373-12 12 0 5.303 3.438 9.8 8.205 11.385.6.113.82-.258.82-.577 0-.285-.01-1.04-.015-2.04-3.338.724-4.042-1.61-4.042-1.61C4.422 18.07 3.633 17.7 3.633 17.7c-1.087-.744.084-.729.084-.729 1.205.084 1.838 1.236 1.838 1.236 1.07 1.835 2.809 1.305 3.495.998.108-.776.417-1.305.76-1.605-2.665-.3-5.466-1.332-5.466-5.93 0-1.31.465-2.38 1.235-3.22-.135-.303-.54-1.523.105-3.176 0 0 1.005-.322 3.3 1.23.96-.267 1.98-.399 3-.405 1.02.006 2.04.138 3 .405 2.28-1.552 3.285-1.23 3.285-1.23.645 1.653.24 2.873.12 3.176.765.84 1.23 1.91 1.23 3.22 0 4.61-2.805 5.625-5.475 5.92.42.36.81 1.096.81 2.22 0 1.606-.015 2.896-.015 3.286 0 .315.21.69.825.57C20.565 22.092 24 17.592 24 12.297c0-6.627-5.373-12-12-12"/></svg></a><!--]--></div></div></div><!--]--><!--]--></div></div></div><!--[--><!--]--><button type="button" class="VPNavBarHamburger hamburger" aria-label="mobile navigation" aria-expanded="false" aria-controls="VPNavScreen" data-v-6f1d18b5 data-v-e5dd9c1c><span class="container" data-v-e5dd9c1c><span class="top" data-v-e5dd9c1c></span><span class="middle" data-v-e5dd9c1c></span><span class="bottom" data-v-e5dd9c1c></span></span></button></div></div></div><!----></header><div class="VPLocalNav" data-v-c6a644e1 data-v-aac27d5e><button class="menu" aria-expanded="false" aria-controls="VPSidebarNav" data-v-aac27d5e><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" viewbox="0 0 24 24" class="menu-icon" data-v-aac27d5e><path d="M17,11H3c-0.6,0-1-0.4-1-1s0.4-1,1-1h14c0.6,0,1,0.4,1,1S17.6,11,17,11z"></path><path d="M21,7H3C2.4,7,2,6.6,2,6s0.4-1,1-1h18c0.6,0,1,0.4,1,1S21.6,7,21,7z"></path><path d="M21,15H3c-0.6,0-1-0.4-1-1s0.4-1,1-1h18c0.6,0,1,0.4,1,1S21.6,15,21,15z"></path><path d="M17,19H3c-0.6,0-1-0.4-1-1s0.4-1,1-1h14c0.6,0,1,0.4,1,1S17.6,19,17,19z"></path></svg><span class="menu-text" data-v-aac27d5e>Menu</span></button><a class="top-link" href="#" data-v-aac27d5e> Return to top </a></div><aside class="VPSidebar" data-v-c6a644e1 data-v-f332cb62><nav class="nav" id="VPSidebarNav" aria-labelledby="sidebar-aria-label" tabindex="-1" data-v-f332cb62><span class="visually-hidden" id="sidebar-aria-label" data-v-f332cb62> Sidebar Navigation </span><!--[--><div class="group" data-v-f332cb62><section class="VPSidebarGroup collapsible" data-v-f332cb62 data-v-2976c796><div class="title" role="button" data-v-2976c796><h2 class="title-text" data-v-2976c796>rust</h2><div class="action" data-v-2976c796><svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" viewbox="0 0 24 24" class="icon minus" data-v-2976c796><path d="M19,2H5C3.3,2,2,3.3,2,5v14c0,1.7,1.3,3,3,3h14c1.7,0,3-1.3,3-3V5C22,3.3,20.7,2,19,2zM20,19c0,0.6-0.4,1-1,1H5c-0.6,0-1-0.4-1-1V5c0-0.6,0.4-1,1-1h14c0.6,0,1,0.4,1,1V19z"></path><path d="M16,11H8c-0.6,0-1,0.4-1,1s0.4,1,1,1h8c0.6,0,1-0.4,1-1S16.6,11,16,11z"></path></svg><svg version="1.1" xmlns="http://www.w3.org/2000/svg" viewbox="0 0 24 24" class="icon plus" data-v-2976c796><path d="M19,2H5C3.3,2,2,3.3,2,5v14c0,1.7,1.3,3,3,3h14c1.7,0,3-1.3,3-3V5C22,3.3,20.7,2,19,2z M20,19c0,0.6-0.4,1-1,1H5c-0.6,0-1-0.4-1-1V5c0-0.6,0.4-1,1-1h14c0.6,0,1,0.4,1,1V19z"></path><path d="M16,11h-3V8c0-0.6-0.4-1-1-1s-1,0.4-1,1v3H8c-0.6,0-1,0.4-1,1s0.4,1,1,1h3v3c0,0.6,0.4,1,1,1s1-0.4,1-1v-3h3c0.6,0,1-0.4,1-1S16.6,11,16,11z"></path></svg></div></div><div class="items" data-v-2976c796><!--[--><!--[--><a class="VPLink link link" href="/articles/rust/01.%E5%9F%BA%E7%A1%80%E5%85%A5%E9%97%A8.html" style="padding-left:0px;" data-v-2cfe069a data-v-3c355974><!--[--><span class="link-text" data-v-2cfe069a>01.基础入门</span><!--]--><!----></a><!----><!--]--><!--[--><a class="VPLink link link" href="/articles/rust/02.%E5%9F%BA%E7%A1%80%E8%AF%AD%E6%B3%95.html" style="padding-left:0px;" data-v-2cfe069a data-v-3c355974><!--[--><span class="link-text" data-v-2cfe069a>02.基础语法</span><!--]--><!----></a><!----><!--]--><!--[--><a class="VPLink link link" href="/articles/rust/03.%E6%8C%87%E9%92%88%E4%B8%8E%E5%86%85%E5%AD%98%E5%88%86%E9%85%8D.html" style="padding-left:0px;" data-v-2cfe069a data-v-3c355974><!--[--><span class="link-text" data-v-2cfe069a>03.指针与内存分配</span><!--]--><!----></a><!----><!--]--><!--[--><a class="VPLink link link" href="/articles/rust/04.%E7%A8%8B%E5%BA%8F%E7%BB%93%E6%9E%84%E5%92%8C%E5%BC%82%E5%B8%B8%E5%A4%84%E7%90%86.html" style="padding-left:0px;" data-v-2cfe069a data-v-3c355974><!--[--><span class="link-text" data-v-2cfe069a>04.程序结构和异常处理</span><!--]--><!----></a><!----><!--]--><!--[--><a class="VPLink link link" href="/articles/rust/05.%E6%95%B0%E6%8D%AE%E7%BB%93%E6%9E%84%E4%B8%8E%E6%B3%9B%E5%9E%8B.html" style="padding-left:0px;" data-v-2cfe069a data-v-3c355974><!--[--><span class="link-text" data-v-2cfe069a>05.数据结构与泛型</span><!--]--><!----></a><!----><!--]--><!--[--><a class="VPLink link link" href="/articles/rust/06.trait%E4%B8%8E%E7%94%9F%E5%91%BD%E5%91%A8%E6%9C%9F.html" style="padding-left:0px;" data-v-2cfe069a data-v-3c355974><!--[--><span class="link-text" data-v-2cfe069a>06.trait与生命周期</span><!--]--><!----></a><!----><!--]--><!--[--><a class="VPLink link link active" href="/articles/rust/07.%E7%BC%96%E5%86%99%E6%B5%8B%E8%AF%95.html" style="padding-left:0px;" data-v-2cfe069a data-v-3c355974><!--[--><span class="link-text" data-v-2cfe069a>07.编写测试</span><!--]--><!----></a><!----><!--]--><!--[--><a class="VPLink link link" href="/articles/rust/08.%E6%9E%84%E5%BB%BA%E5%91%BD%E4%BB%A4%E8%A1%8C%E7%A8%8B%E5%BA%8F.html" style="padding-left:0px;" data-v-2cfe069a data-v-3c355974><!--[--><span class="link-text" data-v-2cfe069a>08.构建命令行程序</span><!--]--><!----></a><!----><!--]--><!--[--><a class="VPLink link link" href="/articles/rust/09.%E9%97%AD%E5%8C%85%E4%B8%8E%E8%BF%AD%E4%BB%A3%E5%99%A8.html" style="padding-left:0px;" data-v-2cfe069a data-v-3c355974><!--[--><span class="link-text" data-v-2cfe069a>09.闭包与迭代器</span><!--]--><!----></a><!----><!--]--><!--[--><a class="VPLink link link" href="/articles/rust/10.%E5%8F%91%E5%B8%83%E9%A1%B9%E7%9B%AE.html" style="padding-left:0px;" data-v-2cfe069a data-v-3c355974><!--[--><span class="link-text" data-v-2cfe069a>10.发布项目</span><!--]--><!----></a><!----><!--]--><!--[--><a class="VPLink link link" href="/articles/rust/11.%E6%99%BA%E8%83%BD%E6%8C%87%E9%92%88.html" style="padding-left:0px;" data-v-2cfe069a data-v-3c355974><!--[--><span class="link-text" data-v-2cfe069a>11.智能指针</span><!--]--><!----></a><!----><!--]--><!--[--><a class="VPLink link link" href="/articles/rust/12.%E5%B9%B6%E5%8F%91.html" style="padding-left:0px;" data-v-2cfe069a data-v-3c355974><!--[--><span class="link-text" data-v-2cfe069a>12.并发</span><!--]--><!----></a><!----><!--]--><!--[--><a class="VPLink link link" href="/articles/rust/13.%E9%9D%A2%E5%90%91%E5%AF%B9%E8%B1%A1.html" style="padding-left:0px;" data-v-2cfe069a data-v-3c355974><!--[--><span class="link-text" data-v-2cfe069a>13.面向对象</span><!--]--><!----></a><!----><!--]--><!--[--><a class="VPLink link link" href="/articles/rust/14.%E4%B8%8D%E5%AE%89%E5%85%A8Rust.html" style="padding-left:0px;" data-v-2cfe069a data-v-3c355974><!--[--><span class="link-text" data-v-2cfe069a>14.不安全Rust</span><!--]--><!----></a><!----><!--]--><!--[--><a class="VPLink link link" href="/articles/rust/15.%E9%AB%98%E7%BA%A7%E7%89%B9%E6%80%A7.html" style="padding-left:0px;" data-v-2cfe069a data-v-3c355974><!--[--><span class="link-text" data-v-2cfe069a>15.高级特性</span><!--]--><!----></a><!----><!--]--><!--[--><a class="VPLink link link" href="/articles/rust/16.%E6%89%8B%E5%86%99web%E6%9C%8D%E5%8A%A1%E5%99%A8%E5%92%8C%E7%BA%BF%E7%A8%8B%E6%B1%A0.html" style="padding-left:0px;" data-v-2cfe069a data-v-3c355974><!--[--><span class="link-text" data-v-2cfe069a>16.手写web服务器和线程池</span><!--]--><!----></a><!----><!--]--><!--[--><a class="VPLink link link" href="/articles/rust/17.rust%E5%BC%82%E6%AD%A5%E7%BC%96%E7%A8%8B.html" style="padding-left:0px;" data-v-2cfe069a data-v-3c355974><!--[--><span class="link-text" data-v-2cfe069a>17.rust异步编程</span><!--]--><!----></a><!----><!--]--><!--]--></div></section></div><div class="group" data-v-f332cb62><section class="VPSidebarGroup collapsible collapsed" data-v-f332cb62 data-v-2976c796><div class="title" role="button" data-v-2976c796><h2 class="title-text" data-v-2976c796>rustweb</h2><div class="action" data-v-2976c796><svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" viewbox="0 0 24 24" class="icon minus" data-v-2976c796><path d="M19,2H5C3.3,2,2,3.3,2,5v14c0,1.7,1.3,3,3,3h14c1.7,0,3-1.3,3-3V5C22,3.3,20.7,2,19,2zM20,19c0,0.6-0.4,1-1,1H5c-0.6,0-1-0.4-1-1V5c0-0.6,0.4-1,1-1h14c0.6,0,1,0.4,1,1V19z"></path><path d="M16,11H8c-0.6,0-1,0.4-1,1s0.4,1,1,1h8c0.6,0,1-0.4,1-1S16.6,11,16,11z"></path></svg><svg version="1.1" xmlns="http://www.w3.org/2000/svg" viewbox="0 0 24 24" class="icon plus" data-v-2976c796><path d="M19,2H5C3.3,2,2,3.3,2,5v14c0,1.7,1.3,3,3,3h14c1.7,0,3-1.3,3-3V5C22,3.3,20.7,2,19,2z M20,19c0,0.6-0.4,1-1,1H5c-0.6,0-1-0.4-1-1V5c0-0.6,0.4-1,1-1h14c0.6,0,1,0.4,1,1V19z"></path><path d="M16,11h-3V8c0-0.6-0.4-1-1-1s-1,0.4-1,1v3H8c-0.6,0-1,0.4-1,1s0.4,1,1,1h3v3c0,0.6,0.4,1,1,1s1-0.4,1-1v-3h3c0.6,0,1-0.4,1-1S16.6,11,16,11z"></path></svg></div></div><div class="items" data-v-2976c796><!--[--><!--[--><a class="VPLink link link" href="/articles/rustweb/01.%E7%AE%80%E5%8D%95%20server.html" style="padding-left:0px;" data-v-2cfe069a data-v-3c355974><!--[--><span class="link-text" data-v-2cfe069a>01.简单 server</span><!--]--><!----></a><!----><!--]--><!--[--><a class="VPLink link link" href="/articles/rustweb/02.Actix.html" style="padding-left:0px;" data-v-2cfe069a data-v-3c355974><!--[--><span class="link-text" data-v-2cfe069a>02.Actix</span><!--]--><!----></a><!----><!--]--><!--[--><a class="VPLink link link" href="/articles/rustweb/03.%E8%BF%9E%E6%8E%A5%E6%95%B0%E6%8D%AE%E5%BA%93.html" style="padding-left:0px;" data-v-2cfe069a data-v-3c355974><!--[--><span class="link-text" data-v-2cfe069a>03.连接数据库</span><!--]--><!----></a><!----><!--]--><!--[--><a class="VPLink link link" href="/articles/rustweb/04.%E9%94%99%E8%AF%AF%E5%A4%84%E7%90%86.html" style="padding-left:0px;" data-v-2cfe069a data-v-3c355974><!--[--><span class="link-text" data-v-2cfe069a>04.错误处理</span><!--]--><!----></a><!----><!--]--><!--[--><a class="VPLink link link" href="/articles/rustweb/05.%E5%AE%8C%E6%95%B4%E9%A1%B9%E7%9B%AE%E9%87%8D%E6%9E%84.html" style="padding-left:0px;" data-v-2cfe069a data-v-3c355974><!--[--><span class="link-text" data-v-2cfe069a>05.完整项目重构</span><!--]--><!----></a><!----><!--]--><!--[--><a class="VPLink link link" href="/articles/rustweb/06.%E6%9C%8D%E5%8A%A1%E5%99%A8%E7%AB%AFweb%E5%BA%94%E7%94%A8.html" style="padding-left:0px;" data-v-2cfe069a data-v-3c355974><!--[--><span class="link-text" data-v-2cfe069a>06.服务器端web应用</span><!--]--><!----></a><!----><!--]--><!--[--><a class="VPLink link link" href="/articles/rustweb/07.WebAssembly.html" style="padding-left:0px;" data-v-2cfe069a data-v-3c355974><!--[--><span class="link-text" data-v-2cfe069a>07.WebAssembly</span><!--]--><!----></a><!----><!--]--><!--[--><a class="VPLink link link" href="/articles/rustweb/08.%E5%8F%91%E5%B8%83.html" style="padding-left:0px;" data-v-2cfe069a data-v-3c355974><!--[--><span class="link-text" data-v-2cfe069a>08.发布</span><!--]--><!----></a><!----><!--]--><!--]--></div></section></div><!--]--></nav></aside><div class="VPContent has-sidebar" id="VPContent" data-v-c6a644e1 data-v-c95df128><div class="VPDoc has-sidebar has-aside" data-v-c95df128 data-v-37ebe389><div class="container" data-v-37ebe389><div class="aside" data-v-37ebe389><div class="aside-curtain" data-v-37ebe389></div><div class="aside-container" data-v-37ebe389><div class="aside-content" data-v-37ebe389><div class="VPDocAside" data-v-37ebe389 data-v-afc4c1a1><!--[--><!--]--><!--[--><!--]--><div class="VPDocAsideOutline" data-v-afc4c1a1 data-v-2865c0b0><div class="content" data-v-2865c0b0><div class="outline-marker" data-v-2865c0b0></div><div class="outline-title" data-v-2865c0b0>On this page</div><nav aria-labelledby="doc-outline-aria-label" data-v-2865c0b0><span class="visually-hidden" id="doc-outline-aria-label" data-v-2865c0b0> Table of Contents for current page </span><ul class="root" data-v-2865c0b0 data-v-1188541a><!--[--><!--]--></ul></nav></div></div><!--[--><!--]--><div class="spacer" data-v-afc4c1a1></div><!--[--><!--]--><!----><!--[--><!--]--><!--[--><!--]--></div></div></div></div><div class="content" data-v-37ebe389><div class="content-container" data-v-37ebe389><!--[--><!--]--><main class="main" data-v-37ebe389><div style="position:relative;" class="vp-doc _articles_rust_07_%E7%BC%96%E5%86%99%E6%B5%8B%E8%AF%95" data-v-37ebe389><div><h1 id="rust入门（七）：编写测试" tabindex="-1">Rust入门（七）：编写测试 <a class="header-anchor" href="#rust入门（七）：编写测试" aria-hidden="true">#</a></h1><p>Rust 中的测试函数是用来验证代码是否是按照你期望的方式运行的一类函数：</p><h2 id="函数测试" tabindex="-1">函数测试 <a class="header-anchor" href="#函数测试" aria-hidden="true">#</a></h2><p>Rust 中的测试就是一个带有 <code>test</code> 属性注解的函数，当使用 <code>cargo test</code> 命令运行测试时，Rust 会构建一个测试执行程序用来调用标记了 <code>test</code> 属性的函数，并报告每一个测试是通过还是失败。</p><div class="language-rust"><button class="copy"></button><span class="lang">rust</span><pre><code><span class="line"><span style="color:#89DDFF;">#[</span><span style="color:#A6ACCD;">test</span><span style="color:#89DDFF;">]</span></span>
<span class="line"><span style="color:#F78C6C;">fn</span><span style="color:#A6ACCD;"> </span><span style="color:#82AAFF;">it_works</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;">   </span><span style="color:#82AAFF;">assert_eq!</span><span style="color:#89DDFF;">(</span><span style="color:#F78C6C;">2</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">+</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">2</span><span style="color:#89DDFF;">,</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">4</span><span style="color:#89DDFF;">);</span></span>
<span class="line"><span style="color:#89DDFF;">}</span></span>
<span class="line"></span></code></pre></div><p>函数体通过使用 <code>assert_eq!</code> 宏来断言 2 加 2 等于 4。一个典型的测试的格式，运行后可以看到，显示了生成的测试函数的名称，它是 <code>it_works</code>，以及测试的运行结果，<code>ok</code>。接着可以看到全体测试运行结果的摘要：<code>test result: ok.</code> 意味着所有测试都通过了。<code>1 passed; 0 failed</code> 表示通过或失败的测试数量。我们并没有将任何测试标记为忽略，所以摘要中会显示 <code>0 ignored</code>。我们也没有过滤需要运行的测试，所以摘要中会显示<code>0 filtered out</code>。<code>0 measured</code> 统计是针对性能测试的</p><div class="language-rust"><button class="copy"></button><span class="lang">rust</span><pre><code><span class="line"><span style="color:#89DDFF;">$</span><span style="color:#A6ACCD;"> cargo test</span></span>
<span class="line"><span style="color:#A6ACCD;">   </span><span style="color:#FFCB6B;">Compiling</span><span style="color:#A6ACCD;"> adder v0</span><span style="color:#89DDFF;">.</span><span style="color:#F78C6C;">1</span><span style="color:#89DDFF;">.</span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;">file</span><span style="color:#89DDFF;">:</span><span style="color:#676E95;">///projects/adder)</span></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#FFCB6B;">Finished</span><span style="color:#A6ACCD;"> test </span><span style="color:#89DDFF;">[</span><span style="color:#A6ACCD;">unoptimized </span><span style="color:#89DDFF;">+</span><span style="color:#A6ACCD;"> debuginfo</span><span style="color:#89DDFF;">]</span><span style="color:#A6ACCD;"> </span><span style="color:#82AAFF;">target</span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;">s</span><span style="color:#89DDFF;">)</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">in</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#89DDFF;">.</span><span style="color:#A6ACCD;">57s</span></span>
<span class="line"><span style="color:#A6ACCD;">     </span><span style="color:#FFCB6B;">Running</span><span style="color:#A6ACCD;"> unittests </span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;">target</span><span style="color:#89DDFF;">/</span><span style="color:#A6ACCD;">debug</span><span style="color:#89DDFF;">/</span><span style="color:#A6ACCD;">deps</span><span style="color:#89DDFF;">/</span><span style="color:#A6ACCD;">adder</span><span style="color:#89DDFF;">-</span><span style="color:#A6ACCD;">92948b65e88960b4</span><span style="color:#89DDFF;">)</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;">running </span><span style="color:#F78C6C;">1</span><span style="color:#A6ACCD;"> test</span></span>
<span class="line"><span style="color:#A6ACCD;">test </span><span style="color:#FFCB6B;">tests</span><span style="color:#89DDFF;">::</span><span style="color:#A6ACCD;">it_works </span><span style="color:#89DDFF;">...</span><span style="color:#A6ACCD;"> ok</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;">test result</span><span style="color:#89DDFF;">:</span><span style="color:#A6ACCD;"> ok</span><span style="color:#89DDFF;">.</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">1</span><span style="color:#A6ACCD;"> passed</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> failed</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> ignored</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> measured</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> filtered out</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> finished </span><span style="color:#F78C6C;">in</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#89DDFF;">.</span><span style="color:#A6ACCD;">00s</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;">   </span><span style="color:#FFCB6B;">Doc</span><span style="color:#89DDFF;">-</span><span style="color:#A6ACCD;">tests adder</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;">running </span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> tests</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;">test result</span><span style="color:#89DDFF;">:</span><span style="color:#A6ACCD;"> ok</span><span style="color:#89DDFF;">.</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> passed</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> failed</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> ignored</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> measured</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> filtered out</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> finished </span><span style="color:#F78C6C;">in</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#89DDFF;">.</span><span style="color:#A6ACCD;">00s</span></span>
<span class="line"></span></code></pre></div><p>当测试函数中出现 panic 时测试就失败了，每一个测试都在一个新线程中运行，当主线程发现测试线程异常了，就将对应测试标记为失败</p><div class="language-rust"><button class="copy"></button><span class="lang">rust</span><pre><code><span class="line"><span style="color:#89DDFF;">#[</span><span style="color:#A6ACCD;">test</span><span style="color:#89DDFF;">]</span></span>
<span class="line"><span style="color:#F78C6C;">fn</span><span style="color:#A6ACCD;"> </span><span style="color:#82AAFF;">another</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#82AAFF;">panic!</span><span style="color:#89DDFF;">(</span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">Make this test fail</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">);</span></span>
<span class="line"><span style="color:#89DDFF;">}</span></span>
<span class="line"></span></code></pre></div><p><code>test tests::another</code> 这一行是 <code>FAILED</code> 而不是 <code>ok</code> 了，只要有一个函数是 FAILED ，则整个函数的测试结果是 FAILED</p><div class="language-rust"><button class="copy"></button><span class="lang">rust</span><pre><code><span class="line"><span style="color:#89DDFF;">$</span><span style="color:#A6ACCD;"> cargo test</span></span>
<span class="line"><span style="color:#A6ACCD;">   </span><span style="color:#FFCB6B;">Compiling</span><span style="color:#A6ACCD;"> adder v0</span><span style="color:#89DDFF;">.</span><span style="color:#F78C6C;">1</span><span style="color:#89DDFF;">.</span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;">file</span><span style="color:#89DDFF;">:</span><span style="color:#676E95;">///projects/adder)</span></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#FFCB6B;">Finished</span><span style="color:#A6ACCD;"> test </span><span style="color:#89DDFF;">[</span><span style="color:#A6ACCD;">unoptimized </span><span style="color:#89DDFF;">+</span><span style="color:#A6ACCD;"> debuginfo</span><span style="color:#89DDFF;">]</span><span style="color:#A6ACCD;"> </span><span style="color:#82AAFF;">target</span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;">s</span><span style="color:#89DDFF;">)</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">in</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#89DDFF;">.</span><span style="color:#A6ACCD;">72s</span></span>
<span class="line"><span style="color:#A6ACCD;">     </span><span style="color:#FFCB6B;">Running</span><span style="color:#A6ACCD;"> unittests </span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;">target</span><span style="color:#89DDFF;">/</span><span style="color:#A6ACCD;">debug</span><span style="color:#89DDFF;">/</span><span style="color:#A6ACCD;">deps</span><span style="color:#89DDFF;">/</span><span style="color:#A6ACCD;">adder</span><span style="color:#89DDFF;">-</span><span style="color:#A6ACCD;">92948b65e88960b4</span><span style="color:#89DDFF;">)</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;">running </span><span style="color:#F78C6C;">2</span><span style="color:#A6ACCD;"> tests</span></span>
<span class="line"><span style="color:#A6ACCD;">test </span><span style="color:#FFCB6B;">tests</span><span style="color:#89DDFF;">::</span><span style="color:#A6ACCD;">another </span><span style="color:#89DDFF;">...</span><span style="color:#A6ACCD;"> FAILED</span></span>
<span class="line"><span style="color:#A6ACCD;">test </span><span style="color:#FFCB6B;">tests</span><span style="color:#89DDFF;">::</span><span style="color:#A6ACCD;">exploration </span><span style="color:#89DDFF;">...</span><span style="color:#A6ACCD;"> ok</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;">failures</span><span style="color:#89DDFF;">:</span></span>
<span class="line"></span>
<span class="line"><span style="color:#89DDFF;">----</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">tests</span><span style="color:#89DDFF;">::</span><span style="color:#A6ACCD;">another stdout </span><span style="color:#89DDFF;">----</span></span>
<span class="line"><span style="color:#A6ACCD;">thread </span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">main</span><span style="color:#89DDFF;">&#39;</span><span style="color:#A6ACCD;"> panicked at </span><span style="color:#89DDFF;">&#39;</span><span style="color:#FFCB6B;">Make</span><span style="color:#A6ACCD;"> this test fail</span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">, src/lib.rs:10:9</span></span>
<span class="line"><span style="color:#C3E88D;">note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace</span></span>
<span class="line"></span>
<span class="line"></span>
<span class="line"><span style="color:#C3E88D;">failures:</span></span>
<span class="line"><span style="color:#C3E88D;">    tests::another</span></span>
<span class="line"></span>
<span class="line"><span style="color:#C3E88D;">test result: FAILED. 1 passed; 1 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s</span></span>
<span class="line"></span>
<span class="line"><span style="color:#C3E88D;">error: test failed, to rerun pass </span><span style="color:#89DDFF;">&#39;</span><span style="color:#89DDFF;">--</span><span style="color:#A6ACCD;">lib</span><span style="color:#89DDFF;">&#39;</span></span>
<span class="line"></span></code></pre></div><h2 id="用于测试的api" tabindex="-1">用于测试的API <a class="header-anchor" href="#用于测试的api" aria-hidden="true">#</a></h2><p><code>assert!</code> 宏由标准库提供，在希望确保测试中一些条件为 <code>true</code> 时非常有用，需要向 <code>assert!</code> 宏提供一个求值为布尔值的参数。如果值是 <code>true</code>，<code>assert!</code> 什么也不做，同时测试会通过。如果值为 <code>false</code>，<code>assert!</code> 调用 <code>panic!</code> 宏，这会导致测试失败</p><div class="language-rust"><button class="copy"></button><span class="lang">rust</span><pre><code><span class="line"><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">#[</span><span style="color:#A6ACCD;">test</span><span style="color:#89DDFF;">]</span></span>
<span class="line"><span style="color:#F78C6C;">fn</span><span style="color:#A6ACCD;"> </span><span style="color:#82AAFF;">test2</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#C792EA;">let</span><span style="color:#A6ACCD;"> re</span><span style="color:#89DDFF;">;</span></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#82AAFF;">if</span><span style="color:#89DDFF;">(</span><span style="color:#F78C6C;">2</span><span style="color:#89DDFF;">+</span><span style="color:#F78C6C;">2</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">==</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">4</span><span style="color:#89DDFF;">){</span></span>
<span class="line"><span style="color:#A6ACCD;">        re </span><span style="color:#89DDFF;">=</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">true;</span></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#89DDFF;">}</span><span style="color:#89DDFF;">else</span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;">        re </span><span style="color:#89DDFF;">=</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">false</span></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#82AAFF;">assert!</span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;">re</span><span style="color:#89DDFF;">);</span></span>
<span class="line"><span style="color:#89DDFF;">}</span></span>
<span class="line"></span></code></pre></div><p><code>assert_eq!</code> 和 <code>assert_ne!</code>。这两个宏分别比较两个值是相等还是不相等。当断言失败时他们也会打印出这两个值具体是什么，以便于观察测试 为什么失败，而 <code>assert!</code> 只会打印出它从 <code>==</code> 表达式中得到了 <code>false</code> 值，而不是导致 <code>false</code> 的两个值。</p><div class="language-rust"><button class="copy"></button><span class="lang">rust</span><pre><code><span class="line"><span style="color:#F78C6C;">pub</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">fn</span><span style="color:#A6ACCD;"> </span><span style="color:#82AAFF;">add_two</span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;">a</span><span style="color:#89DDFF;">:</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">i32</span><span style="color:#89DDFF;">)</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">-&gt;</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">i32</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;">    a </span><span style="color:#89DDFF;">+</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">3</span></span>
<span class="line"><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#89DDFF;">#[</span><span style="color:#A6ACCD;">cfg</span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;">test</span><span style="color:#89DDFF;">)]</span></span>
<span class="line"><span style="color:#C792EA;">mod</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">tests</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#F78C6C;">use</span><span style="color:#FFCB6B;"> </span><span style="color:#A6ACCD;">super</span><span style="color:#89DDFF;">::*;</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#89DDFF;">#[</span><span style="color:#A6ACCD;">test</span><span style="color:#89DDFF;">]</span></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#F78C6C;">fn</span><span style="color:#A6ACCD;"> </span><span style="color:#82AAFF;">it_adds_two</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;">        </span><span style="color:#82AAFF;">assert_eq!</span><span style="color:#89DDFF;">(</span><span style="color:#F78C6C;">4</span><span style="color:#89DDFF;">,</span><span style="color:#A6ACCD;"> </span><span style="color:#82AAFF;">add_two</span><span style="color:#89DDFF;">(</span><span style="color:#F78C6C;">2</span><span style="color:#89DDFF;">));</span></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#89DDFF;">}</span></span>
<span class="line"></span></code></pre></div><p>测试捕获到了 bug！it_adds_two 测试失败，显示信息 assertion failed: <code>(left == right)</code> 并表明 left 是 4 而 right 是 5。这个信息有助于我们开始调试：它说 assert_eq! 的 left 参数是 4，而 right 参数，也就是 add_two(2) 的结果，是 5。</p><div class="language-rust"><button class="copy"></button><span class="lang">rust</span><pre><code><span class="line"><span style="color:#89DDFF;">$</span><span style="color:#A6ACCD;"> cargo test</span></span>
<span class="line"><span style="color:#A6ACCD;">   </span><span style="color:#FFCB6B;">Compiling</span><span style="color:#A6ACCD;"> adder v0</span><span style="color:#89DDFF;">.</span><span style="color:#F78C6C;">1</span><span style="color:#89DDFF;">.</span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;">file</span><span style="color:#89DDFF;">:</span><span style="color:#676E95;">///projects/adder)</span></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#FFCB6B;">Finished</span><span style="color:#A6ACCD;"> test </span><span style="color:#89DDFF;">[</span><span style="color:#A6ACCD;">unoptimized </span><span style="color:#89DDFF;">+</span><span style="color:#A6ACCD;"> debuginfo</span><span style="color:#89DDFF;">]</span><span style="color:#A6ACCD;"> </span><span style="color:#82AAFF;">target</span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;">s</span><span style="color:#89DDFF;">)</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">in</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#89DDFF;">.</span><span style="color:#A6ACCD;">61s</span></span>
<span class="line"><span style="color:#A6ACCD;">     </span><span style="color:#FFCB6B;">Running</span><span style="color:#A6ACCD;"> unittests </span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;">target</span><span style="color:#89DDFF;">/</span><span style="color:#A6ACCD;">debug</span><span style="color:#89DDFF;">/</span><span style="color:#A6ACCD;">deps</span><span style="color:#89DDFF;">/</span><span style="color:#A6ACCD;">adder</span><span style="color:#89DDFF;">-</span><span style="color:#A6ACCD;">92948b65e88960b4</span><span style="color:#89DDFF;">)</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;">running </span><span style="color:#F78C6C;">1</span><span style="color:#A6ACCD;"> test</span></span>
<span class="line"><span style="color:#A6ACCD;">test </span><span style="color:#FFCB6B;">tests</span><span style="color:#89DDFF;">::</span><span style="color:#A6ACCD;">it_adds_two </span><span style="color:#89DDFF;">...</span><span style="color:#A6ACCD;"> FAILED</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;">failures</span><span style="color:#89DDFF;">:</span></span>
<span class="line"></span>
<span class="line"><span style="color:#89DDFF;">----</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">tests</span><span style="color:#89DDFF;">::</span><span style="color:#A6ACCD;">it_adds_two stdout </span><span style="color:#89DDFF;">----</span></span>
<span class="line"><span style="color:#A6ACCD;">thread </span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">main</span><span style="color:#89DDFF;">&#39;</span><span style="color:#A6ACCD;"> panicked at </span><span style="color:#89DDFF;">&#39;</span><span style="color:#FFCB6B;">assertion</span><span style="color:#A6ACCD;"> failed</span><span style="color:#89DDFF;">:</span><span style="color:#A6ACCD;"> `</span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;">left </span><span style="color:#89DDFF;">==</span><span style="color:#A6ACCD;"> right</span><span style="color:#89DDFF;">)</span><span style="color:#A6ACCD;">`</span></span>
<span class="line"><span style="color:#A6ACCD;">  left</span><span style="color:#89DDFF;">:</span><span style="color:#A6ACCD;"> `</span><span style="color:#F78C6C;">4</span><span style="color:#A6ACCD;">`</span><span style="color:#89DDFF;">,</span></span>
<span class="line"><span style="color:#A6ACCD;"> right</span><span style="color:#89DDFF;">:</span><span style="color:#A6ACCD;"> `</span><span style="color:#F78C6C;">5</span><span style="color:#A6ACCD;">`</span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">, src/lib.rs:11:9</span></span>
<span class="line"><span style="color:#C3E88D;">note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace</span></span>
<span class="line"></span>
<span class="line"><span style="color:#C3E88D;">failures:</span></span>
<span class="line"><span style="color:#C3E88D;">    tests::it_adds_two</span></span>
<span class="line"></span>
<span class="line"><span style="color:#C3E88D;">test result: FAILED. 0 passed; 1 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s</span></span>
<span class="line"></span>
<span class="line"><span style="color:#C3E88D;">error: test failed, to rerun pass </span><span style="color:#89DDFF;">&#39;</span><span style="color:#89DDFF;">--</span><span style="color:#A6ACCD;">lib</span><span style="color:#89DDFF;">&#39;</span></span>
<span class="line"></span></code></pre></div><p>属性 <code>should_panic</code> 会让函数中的代码 panic 时会通过，而在其中的代码没有 panic 时失败。<code>#[should_panic]</code> 属性位于 <code>#[test]</code> 之后，对应的测试函数之前</p><div class="language-rust"><button class="copy"></button><span class="lang">rust</span><pre><code><span class="line"><span style="color:#F78C6C;">pub</span><span style="color:#A6ACCD;"> </span><span style="color:#C792EA;">struct</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">Guess</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;">    value</span><span style="color:#89DDFF;">:</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">i32</span><span style="color:#89DDFF;">,</span></span>
<span class="line"><span style="color:#89DDFF;">}</span></span>
<span class="line"></span>
<span class="line"><span style="color:#F78C6C;">impl</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">Guess</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#F78C6C;">pub</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">fn</span><span style="color:#A6ACCD;"> </span><span style="color:#82AAFF;">new</span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;">value</span><span style="color:#89DDFF;">:</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">i32</span><span style="color:#89DDFF;">)</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">-&gt;</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">Guess</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;">        </span><span style="color:#89DDFF;">if</span><span style="color:#A6ACCD;"> value </span><span style="color:#89DDFF;">&lt;</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">1</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">||</span><span style="color:#A6ACCD;"> value </span><span style="color:#89DDFF;">&gt;</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">100</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;">            </span><span style="color:#82AAFF;">panic!</span><span style="color:#89DDFF;">(</span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">Guess value must be between 1 and 100, got </span><span style="color:#89DDFF;">{}</span><span style="color:#C3E88D;">.</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">,</span><span style="color:#A6ACCD;"> value</span><span style="color:#89DDFF;">);</span></span>
<span class="line"><span style="color:#A6ACCD;">        </span><span style="color:#89DDFF;">}</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;">        </span><span style="color:#FFCB6B;">Guess</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span><span style="color:#A6ACCD;"> value </span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#89DDFF;">#[</span><span style="color:#A6ACCD;">cfg</span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;">test</span><span style="color:#89DDFF;">)]</span></span>
<span class="line"><span style="color:#C792EA;">mod</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">tests</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#F78C6C;">use</span><span style="color:#FFCB6B;"> </span><span style="color:#A6ACCD;">super</span><span style="color:#89DDFF;">::*;</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#89DDFF;">#[</span><span style="color:#A6ACCD;">test</span><span style="color:#89DDFF;">]</span></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#89DDFF;">#[</span><span style="color:#A6ACCD;">should_panic</span><span style="color:#89DDFF;">]</span></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#F78C6C;">fn</span><span style="color:#A6ACCD;"> </span><span style="color:#82AAFF;">greater_than_100</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;">        </span><span style="color:#FFCB6B;">Guess</span><span style="color:#89DDFF;">::</span><span style="color:#82AAFF;">new</span><span style="color:#89DDFF;">(</span><span style="color:#F78C6C;">200</span><span style="color:#89DDFF;">);</span></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#89DDFF;">}</span></span>
<span class="line"></span></code></pre></div><div class="language-rust"><button class="copy"></button><span class="lang">rust</span><pre><code><span class="line"><span style="color:#89DDFF;">$</span><span style="color:#A6ACCD;"> cargo test</span></span>
<span class="line"><span style="color:#A6ACCD;">   </span><span style="color:#FFCB6B;">Compiling</span><span style="color:#A6ACCD;"> guessing_game v0</span><span style="color:#89DDFF;">.</span><span style="color:#F78C6C;">1</span><span style="color:#89DDFF;">.</span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;">file</span><span style="color:#89DDFF;">:</span><span style="color:#676E95;">///projects/guessing_game)</span></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#FFCB6B;">Finished</span><span style="color:#A6ACCD;"> test </span><span style="color:#89DDFF;">[</span><span style="color:#A6ACCD;">unoptimized </span><span style="color:#89DDFF;">+</span><span style="color:#A6ACCD;"> debuginfo</span><span style="color:#89DDFF;">]</span><span style="color:#A6ACCD;"> </span><span style="color:#82AAFF;">target</span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;">s</span><span style="color:#89DDFF;">)</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">in</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#89DDFF;">.</span><span style="color:#A6ACCD;">58s</span></span>
<span class="line"><span style="color:#A6ACCD;">     </span><span style="color:#FFCB6B;">Running</span><span style="color:#A6ACCD;"> unittests </span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;">target</span><span style="color:#89DDFF;">/</span><span style="color:#A6ACCD;">debug</span><span style="color:#89DDFF;">/</span><span style="color:#A6ACCD;">deps</span><span style="color:#89DDFF;">/</span><span style="color:#A6ACCD;">guessing_game</span><span style="color:#89DDFF;">-</span><span style="color:#A6ACCD;">57d70c3acb738f4d</span><span style="color:#89DDFF;">)</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;">running </span><span style="color:#F78C6C;">1</span><span style="color:#A6ACCD;"> test</span></span>
<span class="line"><span style="color:#A6ACCD;">test </span><span style="color:#FFCB6B;">tests</span><span style="color:#89DDFF;">::</span><span style="color:#A6ACCD;">greater_than_100 </span><span style="color:#89DDFF;">-</span><span style="color:#A6ACCD;"> should panic </span><span style="color:#89DDFF;">...</span><span style="color:#A6ACCD;"> ok</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;">test result</span><span style="color:#89DDFF;">:</span><span style="color:#A6ACCD;"> ok</span><span style="color:#89DDFF;">.</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">1</span><span style="color:#A6ACCD;"> passed</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> failed</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> ignored</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> measured</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> filtered out</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> finished </span><span style="color:#F78C6C;">in</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#89DDFF;">.</span><span style="color:#A6ACCD;">00s</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;">   </span><span style="color:#FFCB6B;">Doc</span><span style="color:#89DDFF;">-</span><span style="color:#A6ACCD;">tests guessing_game</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;">running </span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> tests</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;">test result</span><span style="color:#89DDFF;">:</span><span style="color:#A6ACCD;"> ok</span><span style="color:#89DDFF;">.</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> passed</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> failed</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> ignored</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> measured</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> filtered out</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> finished </span><span style="color:#F78C6C;">in</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#89DDFF;">.</span><span style="color:#A6ACCD;">00s</span></span>
<span class="line"></span></code></pre></div><p>为了使 <code>should_panic</code> 测试结果更精确，我们可以给 <code>should_panic</code> 属性增加一个可选的 <code>expected</code> 参数。测试工具会确保错误信息中包含其提供的文本，如下的这个测试会通过，因为 <code>should_panic</code> 属性中 <code>expected</code> 参数提供的值是 <code>Guess::new</code> 函数 panic 信息的子串</p><div class="language-rust"><button class="copy"></button><span class="lang">rust</span><pre><code><span class="line"><span style="color:#F78C6C;">impl</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">Guess</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#F78C6C;">pub</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">fn</span><span style="color:#A6ACCD;"> </span><span style="color:#82AAFF;">new</span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;">value</span><span style="color:#89DDFF;">:</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">i32</span><span style="color:#89DDFF;">)</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">-&gt;</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">Guess</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;">        </span><span style="color:#89DDFF;">if</span><span style="color:#A6ACCD;"> value </span><span style="color:#89DDFF;">&lt;</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">1</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;">            </span><span style="color:#82AAFF;">panic!</span><span style="color:#89DDFF;">(</span></span>
<span class="line"><span style="color:#A6ACCD;">                </span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">Guess value must be greater than or equal to 1, got </span><span style="color:#89DDFF;">{}</span><span style="color:#C3E88D;">.</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">,</span></span>
<span class="line"><span style="color:#A6ACCD;">                value</span></span>
<span class="line"><span style="color:#A6ACCD;">            </span><span style="color:#89DDFF;">);</span></span>
<span class="line"><span style="color:#A6ACCD;">        </span><span style="color:#89DDFF;">}</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">else</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">if</span><span style="color:#A6ACCD;"> value </span><span style="color:#89DDFF;">&gt;</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">100</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;">            </span><span style="color:#82AAFF;">panic!</span><span style="color:#89DDFF;">(</span></span>
<span class="line"><span style="color:#A6ACCD;">                </span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">Guess value must be less than or equal to 100, got </span><span style="color:#89DDFF;">{}</span><span style="color:#C3E88D;">.</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">,</span></span>
<span class="line"><span style="color:#A6ACCD;">                value</span></span>
<span class="line"><span style="color:#A6ACCD;">            </span><span style="color:#89DDFF;">);</span></span>
<span class="line"><span style="color:#A6ACCD;">        </span><span style="color:#89DDFF;">}</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;">        </span><span style="color:#FFCB6B;">Guess</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span><span style="color:#A6ACCD;"> value </span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#89DDFF;">}</span></span>
<span class="line"></span>
<span class="line"><span style="color:#89DDFF;">#[</span><span style="color:#A6ACCD;">cfg</span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;">test</span><span style="color:#89DDFF;">)]</span></span>
<span class="line"><span style="color:#C792EA;">mod</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">tests</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#F78C6C;">use</span><span style="color:#FFCB6B;"> </span><span style="color:#A6ACCD;">super</span><span style="color:#89DDFF;">::*;</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#89DDFF;">#[</span><span style="color:#A6ACCD;">test</span><span style="color:#89DDFF;">]</span></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#89DDFF;">#[</span><span style="color:#A6ACCD;">should_panic</span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;">expected </span><span style="color:#89DDFF;">=</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">Guess value must be less than or equal to 100</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">)]</span></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#F78C6C;">fn</span><span style="color:#A6ACCD;"> </span><span style="color:#82AAFF;">greater_than_100</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;">        </span><span style="color:#FFCB6B;">Guess</span><span style="color:#89DDFF;">::</span><span style="color:#82AAFF;">new</span><span style="color:#89DDFF;">(</span><span style="color:#F78C6C;">200</span><span style="color:#89DDFF;">);</span></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#89DDFF;">}</span></span>
<span class="line"></span></code></pre></div><h2 id="自定义错误信息" tabindex="-1">自定义错误信息 <a class="header-anchor" href="#自定义错误信息" aria-hidden="true">#</a></h2><p>你也可以向 <code>assert!</code>、<code>assert_eq!</code> 和 <code>assert_ne!</code> 宏传递一个可选的失败信息参数，可以在测试失败时将自定义失败信息一同打印出来，如下的函数：</p><div class="language-rust"><button class="copy"></button><span class="lang">rust</span><pre><code><span class="line"><span style="color:#89DDFF;">#[</span><span style="color:#A6ACCD;">test</span><span style="color:#89DDFF;">]</span></span>
<span class="line"><span style="color:#F78C6C;">fn</span><span style="color:#A6ACCD;"> </span><span style="color:#82AAFF;">greeting_contains_name</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#C792EA;">let</span><span style="color:#A6ACCD;"> result </span><span style="color:#89DDFF;">=</span><span style="color:#A6ACCD;"> </span><span style="color:#82AAFF;">greeting</span><span style="color:#89DDFF;">(</span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">Carol</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">);</span></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#82AAFF;">assert!</span><span style="color:#89DDFF;">(</span></span>
<span class="line"><span style="color:#A6ACCD;">        result</span><span style="color:#89DDFF;">.</span><span style="color:#82AAFF;">contains</span><span style="color:#89DDFF;">(</span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">Carol</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">),</span></span>
<span class="line"><span style="color:#A6ACCD;">        </span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">Greeting did not contain name, value was `</span><span style="color:#89DDFF;">{}</span><span style="color:#C3E88D;">`</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">,</span></span>
<span class="line"><span style="color:#A6ACCD;">        result</span></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#89DDFF;">);</span></span>
<span class="line"><span style="color:#89DDFF;">}}</span></span>
<span class="line"></span></code></pre></div><p>如果这个函数的运行结果是失败的，将会打印出自定义失败信息参数</p><div class="language-rust"><button class="copy"></button><span class="lang">rust</span><pre><code><span class="line"><span style="color:#89DDFF;">$</span><span style="color:#A6ACCD;"> cargo test</span></span>
<span class="line"><span style="color:#A6ACCD;">   </span><span style="color:#FFCB6B;">Compiling</span><span style="color:#A6ACCD;"> greeter v0</span><span style="color:#89DDFF;">.</span><span style="color:#F78C6C;">1</span><span style="color:#89DDFF;">.</span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;">file</span><span style="color:#89DDFF;">:</span><span style="color:#676E95;">///projects/greeter)</span></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#FFCB6B;">Finished</span><span style="color:#A6ACCD;"> test </span><span style="color:#89DDFF;">[</span><span style="color:#A6ACCD;">unoptimized </span><span style="color:#89DDFF;">+</span><span style="color:#A6ACCD;"> debuginfo</span><span style="color:#89DDFF;">]</span><span style="color:#A6ACCD;"> </span><span style="color:#82AAFF;">target</span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;">s</span><span style="color:#89DDFF;">)</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">in</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#89DDFF;">.</span><span style="color:#A6ACCD;">93s</span></span>
<span class="line"><span style="color:#A6ACCD;">     </span><span style="color:#FFCB6B;">Running</span><span style="color:#A6ACCD;"> unittests </span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;">target</span><span style="color:#89DDFF;">/</span><span style="color:#A6ACCD;">debug</span><span style="color:#89DDFF;">/</span><span style="color:#A6ACCD;">deps</span><span style="color:#89DDFF;">/</span><span style="color:#A6ACCD;">greeter</span><span style="color:#89DDFF;">-</span><span style="color:#A6ACCD;">170b942eb5bf5e3a</span><span style="color:#89DDFF;">)</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;">running </span><span style="color:#F78C6C;">1</span><span style="color:#A6ACCD;"> test</span></span>
<span class="line"><span style="color:#A6ACCD;">test </span><span style="color:#FFCB6B;">tests</span><span style="color:#89DDFF;">::</span><span style="color:#A6ACCD;">greeting_contains_name </span><span style="color:#89DDFF;">...</span><span style="color:#A6ACCD;"> FAILED</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;">failures</span><span style="color:#89DDFF;">:</span></span>
<span class="line"></span>
<span class="line"><span style="color:#89DDFF;">----</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">tests</span><span style="color:#89DDFF;">::</span><span style="color:#A6ACCD;">greeting_contains_name stdout </span><span style="color:#89DDFF;">----</span></span>
<span class="line"><span style="color:#A6ACCD;">thread </span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">main</span><span style="color:#89DDFF;">&#39;</span><span style="color:#A6ACCD;"> panicked at </span><span style="color:#89DDFF;">&#39;</span><span style="color:#FFCB6B;">Greeting</span><span style="color:#A6ACCD;"> did not contain name</span><span style="color:#89DDFF;">,</span><span style="color:#A6ACCD;"> value was `</span><span style="color:#FFCB6B;">Hello!</span><span style="color:#A6ACCD;">`</span><span style="color:#89DDFF;">&#39;</span><span style="color:#C3E88D;">, src/lib.rs:12:9</span></span>
<span class="line"><span style="color:#C3E88D;">note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace</span></span>
<span class="line"></span>
<span class="line"></span>
<span class="line"><span style="color:#C3E88D;">failures:</span></span>
<span class="line"><span style="color:#C3E88D;">    tests::greeting_contains_name</span></span>
<span class="line"></span>
<span class="line"><span style="color:#C3E88D;">test result: FAILED. 0 passed; 1 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s</span></span>
<span class="line"></span>
<span class="line"><span style="color:#C3E88D;">error: test failed, to rerun pass </span><span style="color:#89DDFF;">&#39;</span><span style="color:#89DDFF;">--</span><span style="color:#A6ACCD;">lib</span><span style="color:#89DDFF;">&#39;</span></span>
<span class="line"></span></code></pre></div><h2 id="result测试" tabindex="-1">Result测试 <a class="header-anchor" href="#result测试" aria-hidden="true">#</a></h2><p>我们也可以使用 <code>Result&lt;T, E&gt;</code> 编写测试，使用 <code>Result&lt;T, E&gt;</code> 重写，并在失败时返回 <code>Err</code> 而非 panic，测试通过时返回 <code>Ok(())</code>，在测试失败时返回带有 <code>String</code> 的 <code>Err</code>。</p><div class="language-rust"><button class="copy"></button><span class="lang">rust</span><pre><code><span class="line"><span style="color:#89DDFF;">#[</span><span style="color:#A6ACCD;">cfg</span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;">test</span><span style="color:#89DDFF;">)]</span></span>
<span class="line"><span style="color:#C792EA;">mod</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">tests</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#89DDFF;">#[</span><span style="color:#A6ACCD;">test</span><span style="color:#89DDFF;">]</span></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#F78C6C;">fn</span><span style="color:#A6ACCD;"> </span><span style="color:#82AAFF;">it_works</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">-&gt;</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">Result</span><span style="color:#89DDFF;">&lt;(),</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">String</span><span style="color:#89DDFF;">&gt;</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;">        </span><span style="color:#89DDFF;">if</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">2</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">+</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">2</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">==</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">4</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;">            </span><span style="color:#FFCB6B;">Ok</span><span style="color:#89DDFF;">(())</span></span>
<span class="line"><span style="color:#A6ACCD;">        </span><span style="color:#89DDFF;">}</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">else</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;">            </span><span style="color:#FFCB6B;">Err</span><span style="color:#89DDFF;">(</span><span style="color:#FFCB6B;">String</span><span style="color:#89DDFF;">::</span><span style="color:#82AAFF;">from</span><span style="color:#89DDFF;">(</span><span style="color:#89DDFF;">&quot;</span><span style="color:#C3E88D;">two plus two does not equal four</span><span style="color:#89DDFF;">&quot;</span><span style="color:#89DDFF;">))</span></span>
<span class="line"><span style="color:#A6ACCD;">        </span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#89DDFF;">}</span></span>
<span class="line"></span></code></pre></div><h2 id="控制测试运行" tabindex="-1">控制测试运行 <a class="header-anchor" href="#控制测试运行" aria-hidden="true">#</a></h2><p>当运行多个测试时， Rust 默认使用线程来并行运行。这意味着测试会更快地运行完毕，所以你可以更快的得到代码能否工作的反馈。因为测试是在同时运行的，你应该确保测试不能相互依赖，或依赖任何共享的状态，包括依赖共享的环境，比如当前工作目录或者环境变量。</p><p>举个例子，每一个测试都运行一些代码，假设这些代码都在硬盘上创建一个 <em>test-output.txt</em> 文件并写入一些数据。接着每一个测试都读取文件中的数据并断言这个文件包含特定的值，而这个值在每个测试中都是不同的。因为所有测试都是同时运行的，一个测试可能会在另一个测试读写文件过程中修改了文件。那么第二个测试就会失败，并不是因为代码不正确，而是因为测试并行运行时相互干扰。一个解决方案是使每一个测试读写不同的文件；另一个解决方案是一次运行一个测试。</p><p>如果你不希望测试并行运行，或者想要更加精确的控制线程的数量，可以传递 <code>--test-threads</code> 参数和希望使用线程的数量给测试二进制文件。</p><div class="language-rust"><button class="copy"></button><span class="lang">rust</span><pre><code><span class="line"><span style="color:#89DDFF;">$</span><span style="color:#A6ACCD;"> cargo test </span><span style="color:#89DDFF;">--</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">--</span><span style="color:#A6ACCD;">test</span><span style="color:#89DDFF;">-</span><span style="color:#A6ACCD;">threads</span><span style="color:#89DDFF;">=</span><span style="color:#F78C6C;">1</span></span>
<span class="line"></span></code></pre></div><p>默认情况下，当测试通过时，Rust 的测试库会截获打印到标准输出的所有内容。比如在测试中调用了 <code>println!</code> 而测试通过了，我们将不会在终端看到 <code>println!</code> 的输出：只会看到说明测试通过的提示行。如果测试失败了，则会看到所有标准输出和其他错误信息。</p><p>如果你希望也能看到通过的测试中打印的值，也可以在结尾加上 <code>--show-output</code> 告诉 Rust 显示成功测试的输出。</p><div class="language-rust"><button class="copy"></button><span class="lang">rust</span><pre><code><span class="line"><span style="color:#89DDFF;">$</span><span style="color:#A6ACCD;"> cargo test </span><span style="color:#89DDFF;">--</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">--</span><span style="color:#A6ACCD;">show</span><span style="color:#89DDFF;">-</span><span style="color:#A6ACCD;">output</span></span>
<span class="line"></span></code></pre></div><p>有时运行整个测试集会耗费很长时间。如果你负责特定位置的代码，你可能会希望只运行与这些代码相关的测试。你可以向 <code>cargo test</code> 传递所希望运行的测试名称的参数来选择运行哪些测试。</p><div class="language-rust"><button class="copy"></button><span class="lang">rust</span><pre><code><span class="line"><span style="color:#F78C6C;">pub</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">fn</span><span style="color:#A6ACCD;"> </span><span style="color:#82AAFF;">add_two</span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;">a</span><span style="color:#89DDFF;">:</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">i32</span><span style="color:#89DDFF;">)</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">-&gt;</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">i32</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;">    a </span><span style="color:#89DDFF;">+</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">2</span></span>
<span class="line"><span style="color:#89DDFF;">}</span></span>
<span class="line"></span>
<span class="line"><span style="color:#89DDFF;">#[</span><span style="color:#A6ACCD;">cfg</span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;">test</span><span style="color:#89DDFF;">)]</span></span>
<span class="line"><span style="color:#C792EA;">mod</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">tests</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#F78C6C;">use</span><span style="color:#FFCB6B;"> </span><span style="color:#A6ACCD;">super</span><span style="color:#89DDFF;">::*;</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#89DDFF;">#[</span><span style="color:#A6ACCD;">test</span><span style="color:#89DDFF;">]</span></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#F78C6C;">fn</span><span style="color:#A6ACCD;"> </span><span style="color:#82AAFF;">add_two_and_two</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;">        </span><span style="color:#82AAFF;">assert_eq!</span><span style="color:#89DDFF;">(</span><span style="color:#F78C6C;">4</span><span style="color:#89DDFF;">,</span><span style="color:#A6ACCD;"> </span><span style="color:#82AAFF;">add_two</span><span style="color:#89DDFF;">(</span><span style="color:#F78C6C;">2</span><span style="color:#89DDFF;">));</span></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#89DDFF;">}</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#89DDFF;">#[</span><span style="color:#A6ACCD;">test</span><span style="color:#89DDFF;">]</span></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#F78C6C;">fn</span><span style="color:#A6ACCD;"> </span><span style="color:#82AAFF;">add_three_and_two</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;">        </span><span style="color:#82AAFF;">assert_eq!</span><span style="color:#89DDFF;">(</span><span style="color:#F78C6C;">5</span><span style="color:#89DDFF;">,</span><span style="color:#A6ACCD;"> </span><span style="color:#82AAFF;">add_two</span><span style="color:#89DDFF;">(</span><span style="color:#F78C6C;">3</span><span style="color:#89DDFF;">));</span></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#89DDFF;">}</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#89DDFF;">#[</span><span style="color:#A6ACCD;">test</span><span style="color:#89DDFF;">]</span></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#F78C6C;">fn</span><span style="color:#A6ACCD;"> </span><span style="color:#82AAFF;">one_hundred</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;">        </span><span style="color:#82AAFF;">assert_eq!</span><span style="color:#89DDFF;">(</span><span style="color:#F78C6C;">102</span><span style="color:#89DDFF;">,</span><span style="color:#A6ACCD;"> </span><span style="color:#82AAFF;">add_two</span><span style="color:#89DDFF;">(</span><span style="color:#F78C6C;">100</span><span style="color:#89DDFF;">));</span></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#89DDFF;">}</span></span>
<span class="line"></span></code></pre></div><div class="language-shell"><button class="copy"></button><span class="lang">shell</span><pre><code><span class="line"><span style="color:#A6ACCD;">$ cargo </span><span style="color:#82AAFF;">test</span><span style="color:#A6ACCD;"> one_hundred</span></span>
<span class="line"><span style="color:#A6ACCD;">   Compiling adder v0.1.0 </span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;">file:///projects/adder</span><span style="color:#89DDFF;">)</span></span>
<span class="line"><span style="color:#A6ACCD;">    Finished </span><span style="color:#82AAFF;">test</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">[</span><span style="color:#A6ACCD;">unoptimized + debuginfo</span><span style="color:#89DDFF;">]</span><span style="color:#A6ACCD;"> target</span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;">s</span><span style="color:#89DDFF;">)</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">in</span><span style="color:#A6ACCD;"> 0.69s</span></span>
<span class="line"><span style="color:#A6ACCD;">     Running unittests </span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;">target/debug/deps/adder-92948b65e88960b4</span><span style="color:#89DDFF;">)</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;">running 1 </span><span style="color:#82AAFF;">test</span></span>
<span class="line"><span style="color:#82AAFF;">test</span><span style="color:#A6ACCD;"> tests::one_hundred ... ok</span></span>
<span class="line"></span>
<span class="line"><span style="color:#82AAFF;">test</span><span style="color:#A6ACCD;"> result: ok. 1 passed</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> 0 failed</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> 0 ignored</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> 0 measured</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> 2 filtered out</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> finished </span><span style="color:#89DDFF;">in</span><span style="color:#A6ACCD;"> 0.00s</span></span>
<span class="line"></span></code></pre></div><p>我们可以指定部分测试的名称，任何名称匹配这个名称的测试会被运行。例如，因为头两个测试的名称包含 <code>add</code>，可以通过 <code>cargo test add</code> 来运行这两个测试：</p><div class="language-rust"><button class="copy"></button><span class="lang">rust</span><pre><code><span class="line"><span style="color:#89DDFF;">$</span><span style="color:#A6ACCD;"> cargo test add</span></span>
<span class="line"><span style="color:#A6ACCD;">   </span><span style="color:#FFCB6B;">Compiling</span><span style="color:#A6ACCD;"> adder v0</span><span style="color:#89DDFF;">.</span><span style="color:#F78C6C;">1</span><span style="color:#89DDFF;">.</span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;">file</span><span style="color:#89DDFF;">:</span><span style="color:#676E95;">///projects/adder)</span></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#FFCB6B;">Finished</span><span style="color:#A6ACCD;"> test </span><span style="color:#89DDFF;">[</span><span style="color:#A6ACCD;">unoptimized </span><span style="color:#89DDFF;">+</span><span style="color:#A6ACCD;"> debuginfo</span><span style="color:#89DDFF;">]</span><span style="color:#A6ACCD;"> </span><span style="color:#82AAFF;">target</span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;">s</span><span style="color:#89DDFF;">)</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">in</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#89DDFF;">.</span><span style="color:#A6ACCD;">61s</span></span>
<span class="line"><span style="color:#A6ACCD;">     </span><span style="color:#FFCB6B;">Running</span><span style="color:#A6ACCD;"> unittests </span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;">target</span><span style="color:#89DDFF;">/</span><span style="color:#A6ACCD;">debug</span><span style="color:#89DDFF;">/</span><span style="color:#A6ACCD;">deps</span><span style="color:#89DDFF;">/</span><span style="color:#A6ACCD;">adder</span><span style="color:#89DDFF;">-</span><span style="color:#A6ACCD;">92948b65e88960b4</span><span style="color:#89DDFF;">)</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;">running </span><span style="color:#F78C6C;">2</span><span style="color:#A6ACCD;"> tests</span></span>
<span class="line"><span style="color:#A6ACCD;">test </span><span style="color:#FFCB6B;">tests</span><span style="color:#89DDFF;">::</span><span style="color:#A6ACCD;">add_three_and_two </span><span style="color:#89DDFF;">...</span><span style="color:#A6ACCD;"> ok</span></span>
<span class="line"><span style="color:#A6ACCD;">test </span><span style="color:#FFCB6B;">tests</span><span style="color:#89DDFF;">::</span><span style="color:#A6ACCD;">add_two_and_two </span><span style="color:#89DDFF;">...</span><span style="color:#A6ACCD;"> ok</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;">test result</span><span style="color:#89DDFF;">:</span><span style="color:#A6ACCD;"> ok</span><span style="color:#89DDFF;">.</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">2</span><span style="color:#A6ACCD;"> passed</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> failed</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> ignored</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> measured</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">1</span><span style="color:#A6ACCD;"> filtered out</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> finished </span><span style="color:#F78C6C;">in</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#89DDFF;">.</span><span style="color:#A6ACCD;">00s</span></span>
<span class="line"></span>
<span class="line"></span></code></pre></div><p>虽然可以通过参数列举出所有希望运行的测试来做到，也可以使用 <code>ignore</code> 属性来标记耗时的测试并排除他们</p><div class="language-rust"><button class="copy"></button><span class="lang">rust</span><pre><code><span class="line"><span style="color:#89DDFF;">#[</span><span style="color:#A6ACCD;">test</span><span style="color:#89DDFF;">]</span></span>
<span class="line"><span style="color:#89DDFF;">#[</span><span style="color:#A6ACCD;">ignore</span><span style="color:#89DDFF;">]</span></span>
<span class="line"><span style="color:#F78C6C;">fn</span><span style="color:#A6ACCD;"> </span><span style="color:#82AAFF;">expensive_test</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#676E95;">    // 需要运行一个小时的代码</span></span>
<span class="line"><span style="color:#89DDFF;">}</span></span>
<span class="line"></span></code></pre></div><p>我们在 <code>#[test]</code> 之后增加了 <code>#[ignore]</code> 行。现在如果运行测试，就会发现 <code>it_works</code> 运行了，而 <code>expensive_test</code> 没有运行：</p><div class="language-rust"><button class="copy"></button><span class="lang">rust</span><pre><code><span class="line"><span style="color:#89DDFF;">$</span><span style="color:#A6ACCD;"> cargo test</span></span>
<span class="line"><span style="color:#A6ACCD;">   </span><span style="color:#FFCB6B;">Compiling</span><span style="color:#A6ACCD;"> adder v0</span><span style="color:#89DDFF;">.</span><span style="color:#F78C6C;">1</span><span style="color:#89DDFF;">.</span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;">file</span><span style="color:#89DDFF;">:</span><span style="color:#676E95;">///projects/adder)</span></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#FFCB6B;">Finished</span><span style="color:#A6ACCD;"> test </span><span style="color:#89DDFF;">[</span><span style="color:#A6ACCD;">unoptimized </span><span style="color:#89DDFF;">+</span><span style="color:#A6ACCD;"> debuginfo</span><span style="color:#89DDFF;">]</span><span style="color:#A6ACCD;"> </span><span style="color:#82AAFF;">target</span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;">s</span><span style="color:#89DDFF;">)</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">in</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#89DDFF;">.</span><span style="color:#A6ACCD;">60s</span></span>
<span class="line"><span style="color:#A6ACCD;">     </span><span style="color:#FFCB6B;">Running</span><span style="color:#A6ACCD;"> unittests </span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;">target</span><span style="color:#89DDFF;">/</span><span style="color:#A6ACCD;">debug</span><span style="color:#89DDFF;">/</span><span style="color:#A6ACCD;">deps</span><span style="color:#89DDFF;">/</span><span style="color:#A6ACCD;">adder</span><span style="color:#89DDFF;">-</span><span style="color:#A6ACCD;">92948b65e88960b4</span><span style="color:#89DDFF;">)</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;">running </span><span style="color:#F78C6C;">2</span><span style="color:#A6ACCD;"> tests</span></span>
<span class="line"><span style="color:#A6ACCD;">test expensive_test </span><span style="color:#89DDFF;">...</span><span style="color:#A6ACCD;"> ignored</span></span>
<span class="line"><span style="color:#A6ACCD;">test it_works </span><span style="color:#89DDFF;">...</span><span style="color:#A6ACCD;"> ok</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;">test result</span><span style="color:#89DDFF;">:</span><span style="color:#A6ACCD;"> ok</span><span style="color:#89DDFF;">.</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">1</span><span style="color:#A6ACCD;"> passed</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> failed</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">1</span><span style="color:#A6ACCD;"> ignored</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> measured</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> filtered out</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> finished </span><span style="color:#F78C6C;">in</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#89DDFF;">.</span><span style="color:#A6ACCD;">00s</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;">   </span><span style="color:#FFCB6B;">Doc</span><span style="color:#89DDFF;">-</span><span style="color:#A6ACCD;">tests adder</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;">running </span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> tests</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;">test result</span><span style="color:#89DDFF;">:</span><span style="color:#A6ACCD;"> ok</span><span style="color:#89DDFF;">.</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> passed</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> failed</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> ignored</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> measured</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> filtered out</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> finished </span><span style="color:#F78C6C;">in</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#89DDFF;">.</span><span style="color:#A6ACCD;">00s</span></span>
<span class="line"></span></code></pre></div><p>如果我们只希望运行被忽略的测试，可以使用 <code>cargo test -- --ignored</code>，如果你希望不管是否忽略都要运行全部测试，可以运行 <code>cargo test -- --include-ignored</code></p><div class="language-rust"><button class="copy"></button><span class="lang">rust</span><pre><code><span class="line"><span style="color:#89DDFF;">$</span><span style="color:#A6ACCD;"> cargo test </span><span style="color:#89DDFF;">--</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">--</span><span style="color:#A6ACCD;">ignored</span></span>
<span class="line"><span style="color:#A6ACCD;">   </span><span style="color:#FFCB6B;">Compiling</span><span style="color:#A6ACCD;"> adder v0</span><span style="color:#89DDFF;">.</span><span style="color:#F78C6C;">1</span><span style="color:#89DDFF;">.</span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;">file</span><span style="color:#89DDFF;">:</span><span style="color:#676E95;">///projects/adder)</span></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#FFCB6B;">Finished</span><span style="color:#A6ACCD;"> test </span><span style="color:#89DDFF;">[</span><span style="color:#A6ACCD;">unoptimized </span><span style="color:#89DDFF;">+</span><span style="color:#A6ACCD;"> debuginfo</span><span style="color:#89DDFF;">]</span><span style="color:#A6ACCD;"> </span><span style="color:#82AAFF;">target</span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;">s</span><span style="color:#89DDFF;">)</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">in</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#89DDFF;">.</span><span style="color:#A6ACCD;">61s</span></span>
<span class="line"><span style="color:#A6ACCD;">     </span><span style="color:#FFCB6B;">Running</span><span style="color:#A6ACCD;"> unittests </span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;">target</span><span style="color:#89DDFF;">/</span><span style="color:#A6ACCD;">debug</span><span style="color:#89DDFF;">/</span><span style="color:#A6ACCD;">deps</span><span style="color:#89DDFF;">/</span><span style="color:#A6ACCD;">adder</span><span style="color:#89DDFF;">-</span><span style="color:#A6ACCD;">92948b65e88960b4</span><span style="color:#89DDFF;">)</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;">running </span><span style="color:#F78C6C;">1</span><span style="color:#A6ACCD;"> test</span></span>
<span class="line"><span style="color:#A6ACCD;">test expensive_test </span><span style="color:#89DDFF;">...</span><span style="color:#A6ACCD;"> ok</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;">test result</span><span style="color:#89DDFF;">:</span><span style="color:#A6ACCD;"> ok</span><span style="color:#89DDFF;">.</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">1</span><span style="color:#A6ACCD;"> passed</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> failed</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> ignored</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> measured</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">1</span><span style="color:#A6ACCD;"> filtered out</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> finished </span><span style="color:#F78C6C;">in</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#89DDFF;">.</span><span style="color:#A6ACCD;">00s</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;">   </span><span style="color:#FFCB6B;">Doc</span><span style="color:#89DDFF;">-</span><span style="color:#A6ACCD;">tests adder</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;">running </span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> tests</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;">test result</span><span style="color:#89DDFF;">:</span><span style="color:#A6ACCD;"> ok</span><span style="color:#89DDFF;">.</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> passed</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> failed</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> ignored</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> measured</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> filtered out</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> finished </span><span style="color:#F78C6C;">in</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#89DDFF;">.</span><span style="color:#A6ACCD;">00s</span></span>
<span class="line"></span>
<span class="line"></span></code></pre></div><h2 id="测试组织架构" tabindex="-1">测试组织架构 <a class="header-anchor" href="#测试组织架构" aria-hidden="true">#</a></h2><p>Rust 社区倾向于根据测试的两个主要分类来考虑问题：<strong>单元测试</strong>（<em>unit tests</em>）与 <strong>集成测试</strong>（<em>integration tests</em>）。单元测试倾向于更小而更集中，在隔离的环境中一次测试一个模块，或者是测试私有接口。而集成测试对于你的库来说则完全是外部的。它们与其他外部代码一样，通过相同的方式使用你的代码，只测试公有接口而且每个测试都有可能会测试多个模块。</p><ul><li>单元测试</li></ul><p>单元测试的目的是在与其他部分隔离的环境中测试每一个单元的代码，以便于快速而准确的某个单元的代码功能是否符合预期。</p><p>单元测试与他们要测试的代码共同存放在位于 <em>src</em> 目录下相同的文件中。规范是在每个文件中创建包含测试函数的 <code>tests</code> 模块，并使用 <code>cfg(test)</code> 标注模块。测试模块的 <code>#[cfg(test)]</code> 注解告诉 Rust 只在执行 <code>cargo test</code> 时才编译和运行测试代码，而在运行 <code>cargo build</code> 时不这么做，cfg 属性代表 <em>configuration</em> ，它告诉 Rust 其之后的项只应该被包含进特定配置选项中。在这个例子中，配置选项是 <code>test</code></p><div class="language-rust"><button class="copy"></button><span class="lang">rust</span><pre><code><span class="line"><span style="color:#89DDFF;">#[</span><span style="color:#A6ACCD;">cfg</span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;">test</span><span style="color:#89DDFF;">)]</span></span>
<span class="line"><span style="color:#C792EA;">mod</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">tests</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#89DDFF;">#[</span><span style="color:#A6ACCD;">test</span><span style="color:#89DDFF;">]</span></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#F78C6C;">fn</span><span style="color:#A6ACCD;"> </span><span style="color:#82AAFF;">it_works</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;">        </span><span style="color:#82AAFF;">assert_eq!</span><span style="color:#89DDFF;">(</span><span style="color:#F78C6C;">2</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">+</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">2</span><span style="color:#89DDFF;">,</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">4</span><span style="color:#89DDFF;">);</span></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#89DDFF;">}</span></span>
<span class="line"><span style="color:#89DDFF;">}</span></span>
<span class="line"></span></code></pre></div><ul><li>集成测试</li></ul><p>在 Rust 中，集成测试对于你需要测试的库来说完全是外部的。同其他使用库的代码一样使用库文件，也就是说它们只能调用一部分库中的公有 API ，集成测试的目的是测试库的多个部分能否一起正常工作。</p><p>为了编写集成测试，需要在项目根目录创建一个 <em>tests</em> 目录，与 <em>src</em> 同级。Cargo 知道如何去寻找这个目录中的集成测试文件。接着可以随意在这个目录中创建任意多的测试文件，Cargo 会将每一个文件当作单独的 crate 来编译。</p><p>例子如下：</p><p>创建一个 <em>tests</em> 目录，新建一个文件 <em>tests/integration_test.rs</em>，并输入示例 11-13 中的代码。文件名: tests/integration_test.rs，与单元测试不同，我们需要在文件顶部添加 <code>use adder</code>。这是因为每一个 <code>tests</code> 目录中的测试文件都是完全独立的 crate，所以需要在每一个文件中导入库。<code>tests</code> 文件夹在 Cargo 中是一个特殊的文件夹， Cargo 只会在运行 <code>cargo test</code> 时编译这个目录中的文件。</p><div class="language-rust"><button class="copy"></button><span class="lang">rust</span><pre><code><span class="line"><span style="color:#F78C6C;">use</span><span style="color:#FFCB6B;"> adder</span><span style="color:#89DDFF;">;</span></span>
<span class="line"></span>
<span class="line"><span style="color:#89DDFF;">#[</span><span style="color:#A6ACCD;">test</span><span style="color:#89DDFF;">]</span></span>
<span class="line"><span style="color:#F78C6C;">fn</span><span style="color:#A6ACCD;"> </span><span style="color:#82AAFF;">it_adds_two</span><span style="color:#89DDFF;">()</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">{</span></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#82AAFF;">assert_eq!</span><span style="color:#89DDFF;">(</span><span style="color:#F78C6C;">4</span><span style="color:#89DDFF;">,</span><span style="color:#A6ACCD;"> </span><span style="color:#FFCB6B;">adder</span><span style="color:#89DDFF;">::</span><span style="color:#82AAFF;">add_two</span><span style="color:#89DDFF;">(</span><span style="color:#F78C6C;">2</span><span style="color:#89DDFF;">));</span></span>
<span class="line"><span style="color:#89DDFF;">}</span></span>
<span class="line"></span></code></pre></div><p>也可以使用 <code>cargo test</code> 的 <code>--test</code> 后跟文件的名称来运行某个特定集成测试文件中的所有测试：</p><div class="language-rust"><button class="copy"></button><span class="lang">rust</span><pre><code><span class="line"><span style="color:#89DDFF;">$</span><span style="color:#A6ACCD;"> cargo test </span><span style="color:#89DDFF;">--</span><span style="color:#A6ACCD;">test integration_test</span></span>
<span class="line"><span style="color:#A6ACCD;">   </span><span style="color:#FFCB6B;">Compiling</span><span style="color:#A6ACCD;"> adder v0</span><span style="color:#89DDFF;">.</span><span style="color:#F78C6C;">1</span><span style="color:#89DDFF;">.</span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> </span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;">file</span><span style="color:#89DDFF;">:</span><span style="color:#676E95;">///projects/adder)</span></span>
<span class="line"><span style="color:#A6ACCD;">    </span><span style="color:#FFCB6B;">Finished</span><span style="color:#A6ACCD;"> test </span><span style="color:#89DDFF;">[</span><span style="color:#A6ACCD;">unoptimized </span><span style="color:#89DDFF;">+</span><span style="color:#A6ACCD;"> debuginfo</span><span style="color:#89DDFF;">]</span><span style="color:#A6ACCD;"> </span><span style="color:#82AAFF;">target</span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;">s</span><span style="color:#89DDFF;">)</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">in</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#89DDFF;">.</span><span style="color:#A6ACCD;">64s</span></span>
<span class="line"><span style="color:#A6ACCD;">     </span><span style="color:#FFCB6B;">Running</span><span style="color:#A6ACCD;"> tests</span><span style="color:#89DDFF;">/</span><span style="color:#A6ACCD;">integration_test</span><span style="color:#89DDFF;">.</span><span style="color:#A6ACCD;">rs </span><span style="color:#89DDFF;">(</span><span style="color:#A6ACCD;">target</span><span style="color:#89DDFF;">/</span><span style="color:#A6ACCD;">debug</span><span style="color:#89DDFF;">/</span><span style="color:#A6ACCD;">deps</span><span style="color:#89DDFF;">/</span><span style="color:#A6ACCD;">integration_test</span><span style="color:#89DDFF;">-</span><span style="color:#A6ACCD;">82e7799c1bc62298</span><span style="color:#89DDFF;">)</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;">running </span><span style="color:#F78C6C;">1</span><span style="color:#A6ACCD;"> test</span></span>
<span class="line"><span style="color:#A6ACCD;">test it_adds_two </span><span style="color:#89DDFF;">...</span><span style="color:#A6ACCD;"> ok</span></span>
<span class="line"></span>
<span class="line"><span style="color:#A6ACCD;">test result</span><span style="color:#89DDFF;">:</span><span style="color:#A6ACCD;"> ok</span><span style="color:#89DDFF;">.</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">1</span><span style="color:#A6ACCD;"> passed</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> failed</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> ignored</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> measured</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#A6ACCD;"> filtered out</span><span style="color:#89DDFF;">;</span><span style="color:#A6ACCD;"> finished </span><span style="color:#F78C6C;">in</span><span style="color:#A6ACCD;"> </span><span style="color:#F78C6C;">0</span><span style="color:#89DDFF;">.</span><span style="color:#A6ACCD;">00s</span></span>
<span class="line"></span>
<span class="line"></span></code></pre></div><p>如果项目是二进制 crate 并且只包含 <em>src/main.rs</em> 而没有 <em>src/lib.rs</em>，这样就不可能在 <em>tests</em> 目录创建集成测试并使用 <code>extern crate</code> 导入 <em>src/main.rs</em> 中定义的函数。只有库 crate 才会向其他 crate 暴露了可供调用和使用的函数；二进制 crate 只意在单独运行。</p></div></div></main><!--[--><!--]--><footer class="VPDocFooter" data-v-37ebe389 data-v-a54a85bd><!----><div class="prev-next" data-v-a54a85bd><div class="pager" data-v-a54a85bd><a class="pager-link prev" href="/articles/rust/06.trait%E4%B8%8E%E7%94%9F%E5%91%BD%E5%91%A8%E6%9C%9F.html" data-v-a54a85bd><span class="desc" data-v-a54a85bd>Previous page</span><span class="title" data-v-a54a85bd>06.trait与生命周期</span></a></div><div class="has-prev pager" data-v-a54a85bd><a class="pager-link next" href="/articles/rust/08.%E6%9E%84%E5%BB%BA%E5%91%BD%E4%BB%A4%E8%A1%8C%E7%A8%8B%E5%BA%8F.html" data-v-a54a85bd><span class="desc" data-v-a54a85bd>Next page</span><span class="title" data-v-a54a85bd>08.构建命令行程序</span></a></div></div></footer><!--[--><!--]--></div></div></div></div></div><!----><!--[--><!--]--></div></div>
    <script>__VP_HASH_MAP__ = JSON.parse("{\"articles_basic-bitdance_class01-html.md\":\"ff4ff513\",\"articles_basic-bitdance_class02-css.md\":\"a702a9f8\",\"articles_basic-bitdance_class03-js.md\":\"0cf4e640\",\"articles_basic-bitdance_class04-typescript.md\":\"6eb8a62e\",\"articles_basic-bitdance_class05-http.md\":\"cb129388\",\"articles_basic-bitdance_class06-react.md\":\"a4c71f1a\",\"articles_basic-bitdance_class07-node.md\":\"7925a6b7\",\"articles_basic-bitdance_class08-next.js.md\":\"893eef63\",\"articles_basic-bitdance_class08.5-开发技巧.md\":\"e6d7e150\",\"articles_basic-bitdance_class09-跨端技术.md\":\"25156c46\",\"articles_basic-bitdance_class10-调试.md\":\"f07f60c2\",\"articles_basic-bitdance_class11-安全.md\":\"3c992463\",\"articles_basic-bitdance_class12-监控sdk.md\":\"35ef00f1\",\"articles_basic-bitdance_class13-webpack.md\":\"70e5acc7\",\"articles_basic-bitdance_class14-vite.md\":\"9cfa31e3\",\"articles_basic-bitdance_class15-可视化.md\":\"4c9a2433\",\"articles_basic_index.md\":\"5c1f50b5\",\"articles_electron_index.md\":\"acb5a448\",\"articles_electron_测试.md\":\"5404a20a\",\"articles_mini_index.md\":\"9af79c7b\",\"articles_other_vitepress_01.vitepress的搭建.md\":\"b8deb5b2\",\"articles_other_vitepress_02.vitepress的部署.md\":\"cf416a09\",\"articles_other_vitepress_03.vitepress自动生成目录.md\":\"0dd6d021\",\"articles_other_vitepress_04.vitepress引入vue组件.md\":\"46052034\",\"articles_react_index.md\":\"ec69e04d\",\"articles_react_source code_01.react的架构.md\":\"f4181c9b\",\"articles_rust_01.基础入门.md\":\"af35ebe7\",\"articles_rust_02.基础语法.md\":\"eba033ca\",\"articles_rust_03.指针与内存分配.md\":\"b6d4df62\",\"articles_rust_04.程序结构和异常处理.md\":\"07567152\",\"articles_rust_05.数据结构与泛型.md\":\"6d5c530d\",\"articles_rust_06.trait与生命周期.md\":\"5e57b7aa\",\"articles_rust_07.编写测试.md\":\"bd7d6015\",\"articles_rust_08.构建命令行程序.md\":\"a295a848\",\"articles_rust_09.闭包与迭代器.md\":\"cf79a80f\",\"articles_rust_10.发布项目.md\":\"9e4f6be1\",\"articles_rust_11.智能指针.md\":\"48ecbccd\",\"articles_rust_12.并发.md\":\"62f8f67e\",\"articles_rust_13.面向对象.md\":\"a8519b1a\",\"articles_rust_14.不安全rust.md\":\"a079df80\",\"articles_rust_15.高级特性.md\":\"2b09c61c\",\"articles_rust_16.手写web服务器和线程池.md\":\"97f59e40\",\"articles_rust_17.rust异步编程.md\":\"e26606a3\",\"articles_rustweb_01.简单 server.md\":\"6c2ab750\",\"articles_rustweb_02.actix.md\":\"048a9c59\",\"articles_rustweb_03.连接数据库.md\":\"5ccb794e\",\"articles_rustweb_04.错误处理.md\":\"bd3759f6\",\"articles_rustweb_05.完整项目重构.md\":\"d160a226\",\"articles_rustweb_06.服务器端web应用.md\":\"cdc4f4ca\",\"articles_rustweb_07.webassembly.md\":\"0f1bc773\",\"articles_rustweb_08.发布.md\":\"d4792485\",\"articles_vue_index.md\":\"5ded6ffa\",\"articles_vue组件库_vue3组件库项目学习笔记（1）：基础搭建.md\":\"23c5186c\",\"articles_vue组件库_vue3组件库项目学习笔记（2）：开发一个组件.md\":\"fdd9e315\",\"articles_vue组件库_vue3组件库项目学习笔记（3）：测试你的组件.md\":\"7a02b7b2\",\"articles_vue组件库_vue3组件库项目学习笔记（4）：发布你的组件.md\":\"e0b3816e\",\"articles_vue组件库_vue3组件库项目学习笔记（5）：配置编码规范.md\":\"291e9a8e\",\"articles_vue组件库_vue3组件库项目学习笔记（6）：发布组件文档.md\":\"3fa49d31\",\"articles_vue组件库_vue3组件库项目学习笔记（7）：正式开发问题拾遗.md\":\"85204ad9\",\"articles_vue组件库_vue3组件库项目学习笔记（8）：git协作.md\":\"ab61313a\",\"articles_web3d_index.md\":\"a52fc82e\",\"index.md\":\"de494fc0\",\"intent_index.md\":\"82efde64\",\"leetcode_leet_code题解_47. 全排列 ii.md\":\"c8680b3d\",\"leetcode_leet_code题解_49. 字母异位词分组.md\":\"e37b3116\",\"leetcode_leet_code题解_55. 跳跃游戏.md\":\"29658916\",\"leetcode_leet_code题解_56. 合并区间.md\":\"8f16bd71\",\"public_draco_readme.md\":\"5da4c955\"}")</script>
    <script type="module" async src="/assets/app.75d9ecf2.js"></script>
    
  </body>
</html>